tions, some of which can cause physical limitation. Morbidly obese patients are also limited by their body habitus and weight related pain; this is especially true in the super morbidly obese patients. The limitations in mobility can impede on preoperative weight loss, cause psychological stress and limit access to care [101]. Preoperative functional status should be evaluated as it has been shown to be the strongest predictor for postoperative in hospital morbidity and mortality [102]. Our previously published data revealed that a completely dependent patient was 27 times more likely to experience mortality after bariatric surgery. The information gained from investigations into the patient's functional status is shared with the patient and risks, benefits and alternatives are discussed with the ability to offer a reasonable

Preoperative exercise has been found to reduce surgical complications, facilitate healing, achieve the mindset needed for positive behavior changes, and augment the rate of increased postoperative physical activity [103]. The ASMBS suggests exercise for 20 minutes, three to four days a week is sufficient to achieve these results [104]. Most bariatric surgery patients have sedentary lifestyles and low physical activity level. King and Bond describe a five step process to providing physical activity counseling to patients undergo‐

The first step is to assess the patient's knowledge, beliefs and values regarding exercise along with prior and current levels of physical activity. The potential barriers successful implemen‐ tation of a physical activity program should also be investigated at this point. Prior to begin‐ ning a physical activity program, the patients with current or a history of exercise intolerance should be referred to a cardiologist for proper exercise testing. Aside from cardiopulmonary restrictions to exercise, patients should be assessed for physical limitations such as sensory,

The second step is to advise the patient on the benefits of physical activity and develop realistic expectations. Strategies to increase safety and decrease barriers should be established. The patients should be taught how to gauge the level of intensity using the talk test or by measuring

The thirds step is to come to a mutual agreement with the patient regarding their short, intermediate and long term physical activity goals. The goals should not be end results such as weight loss or maximal activity, but rather, specific goals regarding the frequency, duration and type of physical activity performed. It is recommended that the clinician set one goal that the patient has a high likelihood of achieving to boost confidence and encourage the patient

The fourth step is to assist the patient in achieving the goals by providing the patient printed materials and other resources that support self monitored physical activity. Such items include diaries, pedometers and a list of safe walking paths or fitness facilities. Patients who need a high level of encouragement or guidance, and those with significant barriers should be referred to professional personal trainers or other exercise professionals to achieve the best results. The final step is to arrange for follow up and monitoring to answer questions and provide reinforcement. The patient and clinician should not be discouraged if the level of physical

balance and gait abnormalities – all of which can increase the risk of injury.

to continue increasing their level of physical activity.

prognosis of the postoperative period.

22 Essentials and Controversies in Bariatric Surgery

ing weight loss surgery [103].

their own heart rate.

The preoperative evaluation of the bariatric surgery patient requires a multidisciplinary approach, ultimately coordinated by the surgeon. There are many details to which attention must be paid including medical, nutritional and psychological aspects in an effort to fully evaluate the patient as a whole. This multi faceted approach is one of the factors which have allowed bariatric surgery to become a safe and effective method for weight loss and comor‐ bidity amelioration. These evaluations may reveal problems which should be addressed before surgery to ensure safety and success in the postoperative period. These assessments offer the best way to prepare and counsel a patient for these life altering operations and provide a reasonable basis of expectation on the part of the surgeon and the patient. Many of the learning points incorporated into the preoperative evaluation of bariatric patients can potentially be applied to other disciplines.

## **Author details**

Gurdeep S. Matharoo1 , Erika Renick1 , John N. Afthinos1 , Tracey Straker2 and Karen E. Gibbs1\*

\*Address all correspondence to<EMAIL_ADDRESS>
1 Department of Surgery, Division of Minimally Invasive and Bariatric Surgery, Staten Island University Hospital, State University of New York, Brooklyn, USA

2 Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, New York, USA

## **References**

[3] Fried M, Yumuk V, Oppert J, et al. Interdisciplinary European guidelines on meta‐ bolic and bariatric surgery. Obes Fact. 2013;6:449-68.

[15] Darvish-Kazem S, Gandhi M, Marcucci M, et al. Perioperative management of anti‐ platelet therapy in patients with a coronary stent who need non-cardiac surgery: a systematic review of clinical practice guidelines. Chest. 2013 Aug 8. Epub ahead of

Preoperative Evaluation of Bariatric Surgery Patients

http://dx.doi.org/10.5772/58605

25

[16] Khan MF, Movahed MR. Obesity cardiomyopathy and systolic function: obesity is not independently associated withdilated cardiomyopathy. Heart Fail Rev.

[17] Allman-Farinelli MA. Obesity and venous thrombosis: a review. Semin Thromb He‐

[18] Mertens I, Van Gaal LF. Obesity, haemostasis and the fibrinolytic system. Obes Rev

[19] Kuruba R, Koche LS, Murr MM. Preoperative assessment and perioperative care of

[20] The American Society for Metabolic and Bariatric Surgery Clinical Issues Committee. ASMBS updated position statement on prophylactic measures to reduce the risk of venous thromboembolism in bariatric surgery patients. Surg Obes Relat Dis.

[21] Zierler BK. Ultrasonography and diagnosis of venous thromboembolism. Circula‐

[22] Prystowsky JB, Morasch MD, Eskandari, MK, et al. Prospective analysis of the inci‐ dence of deep venous thrombosis in bariatric surgery patients. Surgery.

[23] Westling A, Bergqvist D, Bostrom A. Incidence of deep venous thrombosis in pa‐

[24] Gargiulo NJ 3rd, Veith FJ, Lipsitz EC, et al. The incidence of pulmonary embolism in

[25] Gargiulo NJ 3rd, O'Connor DJ, Veith FJ, et al. Long-term outcome of inferior vena cava filter placement in patients undergoing gastric bypass. Ann Vasc Surg.

[26] Birkmeyer NJO, Share D, Baser O, et al. Preoperative placement of inferior vena cava filters and outcomes after gastric bypass surgery. Ann Surg. 2010;252:313-8.

[27] U.S. Food and Drug Administration. Removing retrievable inferior vena cava filters: initial communication. August 9, 2010. Available at: http://www.fda.gov/MedicalDe‐

[28] Birkmeyer NJ, Finks JF, English WJ, et al. Risk and benefits of prophylactic inferior vena cava filters in patients undergoing bariatric surgery. Journal of Hospital Medi‐

vices/Safety/AlertsandNotices/ucm221676.htm. Accessed November 2, 2013.

open versus laparoscopic gastric bypass. Ann Vasc Surg. 2007;21:556-9.

tients undergoing obesity surgery. World J Surg. 2002;26:470-3.

patients undergoing bariatric surgery. Med Clin N Am. 2007;339-51.

print

2013;18:207-17.

2002;3:85-101.

2013;9:493-97

tion. 2004;109:I9-I14.

2005;138:759-65.

2010;24:946-9.

cine. 2013;8:173-77.

most 2011;37:903-7.

[15] Darvish-Kazem S, Gandhi M, Marcucci M, et al. Perioperative management of anti‐ platelet therapy in patients with a coronary stent who need non-cardiac surgery: a systematic review of clinical practice guidelines. Chest. 2013 Aug 8. Epub ahead of print

[3] Fried M, Yumuk V, Oppert J, et al. Interdisciplinary European guidelines on meta‐

[4] Snijder MB, van Dam RM, Visser M, et al. What aspect of body fat are particularly hazardous and how do we measure them? Int J Epidemiol. 2006;35(1)83-92.

[5] Kasama K, Mui W, Lee WJ, et al. IFSO-APC Consensus Statements 2011. Obes Surg.

[6] Zalesin KC, Franklin BA, Miller WM, et al. Impact of obesity on cardiovascular dis‐

[7] Fleisher LA, Beckman JA, Brown KA, et al. ACC/AHA 2007 guidelines on periopera‐ tive cardiovascular evaluation and care for noncardiac surgery: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). Circulation.

[8] Mokdad, AH, Ford ES, Bowman BA, et al. Prevalence of obesity, diabetes and obesi‐

[9] Padwal RS, Chang H, Klarenbach S, et al. Characteristic of the population eligible for and receiving publicly funded bariatric surgery in Canada. International Journal of

[10] DeMaria EJ, Portenier D, Wolfe L. Obesity surgery mortality risk score: proposal for a clnically useful score to predict mortality risk in patients undergoing gastric by‐

[11] Fleisher LA, Beckman JA, Brown KA, et al. 2009 ACCF/AHA focused update on peri‐ operative beta blockade incorporated into the ACC/AHA 2007 guidelines on perio‐ perative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology Foundation/American Heart Association Task Force

[12] Katkhouda N, Mason RJ, Wu B, et al. Evaluation and treatment of patients with car‐ diac disease undergoing bariatric surgery. Surg Obes Relat Dis. 2012;8:634-40.

[13] Hansen CL, Woodhouse s, Kramer M. Effect of patient obesity on the accuracy of

[14] Fihn SD, Gardin JM, Abrams J, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and In‐ terventions, and Society of Thoracic Surgeons. J Am Coll Cardiol 2012;60:e44–164.

thallium-201 myocardial perfusion imaging. Am J Cardiol 2000;85:749-52

ty-related health risk factors, 2001. JAMA. 2003;289;76-79.

on Practice Guidelines. J Am Coll Cardiol. 2009;54:e13–118.

bolic and bariatric surgery. Obes Fact. 2013;6:449-68.

ease. Med Clin N Am. 2011;95:919-937.

2012;22:677-84.

24 Essentials and Controversies in Bariatric Surgery

2007;116:1971–1996.

Equity in Health. 2012; 11:54.

pass. Surg Obes Relat Dis. 2007;3:134-40.

[29] Hsu P, Basu CB, Venturi M, et al. Venous thromboembolism prophylaxis. Semin Plast Surg. 2006;20(4):225-32.

[43] Chau EHL, Lam D, Wong J, et al. Obesity hypoventilation syndrome a review of epi‐ demiology, pathophysiology, and perioperative considerations. Anesthesiology.

Preoperative Evaluation of Bariatric Surgery Patients

http://dx.doi.org/10.5772/58605

27

[44] Khan A, King WB, Patterson EJ, et al. Assessment of obstructive sleep apnea in adults undergoing bariatric surgery in the Longitudinal Assessment of Bariatric Sur‐

[45] Ogunnaike B, Jones SB, Jones DB, et al. Anesthetic considerations for bariatric sur‐

[46] Kheterpal S, Han R, Tremper KK, et al. Incidence and predictors of difficult mask

[47] Neligan PJ, Porter s, Max B, et al. Obstructive sleep apnea is not a risk factor for diffi‐ cult intubation in morbidly obese patients. Anesth Analg. 2009;109(4):1182-6.

[48] Lebowitz PW, Shay H, Straker T,et al. Shoulder and head elevation improves lar‐ yngoscopic view for tracheal intubation in non obese as well as obese individuals. J

[49] Brodsky JB, Lemmens JM, Brock-Utne JG, et al. Morbid obesity and tracheal intuba‐

[50] Vaugh RW, Bauer S, Wise L. Volume and pH of gastric juice in obese patients. Anes‐

[51] Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118(2):

[52] Anesthesiology News – Guide to Airway Management. Airway management in the patient undergoing bariatric surgery. Available at http://www.anesthesiology‐ news.com/download/Bariatric\_ANGAM09\_WM.pdf. Accesibility verified: Novem‐

[53] Mechanick JI, Youdim A, Jones DB, et al. Clinical practice guidelines for the perioper‐ ative nutritional, metabolic, and nonsurgical support of the bariatric surgery pa‐ tient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariat‐

[54] Jankovic D, Wolf P, Anderwald C, et al. Prevalence of endocrine disorders in mor‐ bidly obese patients and the effects of bariatric surgery on endocrine and metabolic

gery-2 (LABS-2) study. J Clin Sleep Med. 2013;9(1):21-9.

gery. Anesth Analg. 2002;95:1793-1805.

Clin Anesth. 2012;24(2):104-8.

thesiology 1975;43(6):686-689.

251-70

ber 4, 2013.

tion. Anesth Analg. 2002;94(3):732-736.

ric Surgery. Surg Obes Relat Dis. 2013;9:159-91.

parameters. Obes Surg. 2012;22:62-69.

ventilation. Anesthesiology 2006;105(5):885-891.

2012;117:118-205

[43] Chau EHL, Lam D, Wong J, et al. Obesity hypoventilation syndrome a review of epi‐ demiology, pathophysiology, and perioperative considerations. Anesthesiology. 2012;117:118-205

[29] Hsu P, Basu CB, Venturi M, et al. Venous thromboembolism prophylaxis. Semin

[30] Becattini C, Agnelli G, Manina G, et al. Venous thromboembolism after laparoscopic bariatric surgery for morbid obesity: clinical burden and preventions. Surg Obes Re‐

[31] Kemkes-Matthes B. Hirudin for prophylaxis and treatment of deep vein thrombosis.

[32] Mosen DM, Schatz M, Magid DJ, et al. The relationship between obesity and asthma severity and control in adults. J Allergy Clin Immunol. 2008;122:507-11. e6.

[33] Beuther DA, Sutherland ER. Overweight, obesity and incident asthma: a meta-analy‐ sis of prospective epidemiologic studies. Am J Respir Crit Care Med. 2007;175:661-6

[34] Hamoui N, Anthone G, Crookes PF. The value of pulmonary function testing prior to

[35] van Huisstede A, Biter LU, Luitwieler R, et al. Pulmonary function testing and com‐ plications of laparoscopic bariatric surgery. Obes Surg. 2013;23:1596-1603.

[36] Masoomi H, Reavis KM, Smith BR, et al. Risk factors for acutre respiratory failure in bariatric surgery: data from the Nationwide Inpatient Sample, 2006 – 2008. Surg

[37] Marchini JFM, Souza FLN, Schmidt A, et al. Low educational status, smoking, and multidisciplinary team experience predict hospital length of stay after bariatric sur‐

[38] Azagury DE, Abu Dayyeh BK, Greenwalt IT, et al. Marginal ulceration after roux-eny gastric bypass surgery: characteristics, risk factors, treatment, and outcomes. En‐

[39] Fawcett A, Shembekar M, Church JS, et al. Smoking, hypertension, and colonic anas‐ tomotic healing; a combinded clinical and histopathological study. Gut.

[40] ASMBS Clinical Issues Committee et al. Perioperative management of obstructive

[41] Berry RB; Budhiraja R; Gottlieb DJ; et al. Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. J

[42] Ramirez A, Lalor PF, Szomstein S, et al. Continuous positive airway pressure in im‐ mediate postoperative period after laparoscopic roux-en-y gastric bypass: is it safe?

Plast Surg. 2006;20(4):225-32.

Semin Thromb Hemost. 2002;28(5):455-8.

bariatric surgery. Obes Surg. 2006;16:1570-73

Obes Relat Dis. 2013;9:277-83.

doscopy. 2011;43:950-4.

1996;38:714-8.

gery. Nutr Metab Insights. 2012;5:71-6.

sleep apnea. Surg Obes Relat Dis. 2012;8:e27-e32.

Clin Sleep Med 2012;8(5):597-619.

Surg Obes Relat Dis. 2009;5:544-6.

lat Dis 2012;8:108-15

26 Essentials and Controversies in Bariatric Surgery

[55] Perna M, Romagnuolo J, Morgan K et al. Preoperative hemoglobin A1c and postop‐ erative glucose control in outcomes after gastric bypass for obesity. Surg Obes Relat Dis. 2012;6:686-90.

[70] Aills L, Blankenship J, Buffington C, et al. ASMBS allied health nutritional guidelines for the surgical weight loss patient. Surg Obes Relat Dis. 2008;4(5 Suppl):S73-S108.

Preoperative Evaluation of Bariatric Surgery Patients

http://dx.doi.org/10.5772/58605

29

[71] National Eating Disorders Association. Factors that may contribute to eating disor‐ ders page. Accessibility verified: http://www.nationaleatingdisorders.org/contribu‐

[72] Beckman LM, Beckman TR, Earthman CP. Changes in gastrointestinal hormones and leptin after Roux-en-Y gastric bypass procedure: a review. J Am diet Assoc.

[73] Karpyn A, Young C, Weiss S. Reestablishing healthy food retail: changing the land‐

[74] Herichova I. Changes of physiological functions induced by shift work. Endocr Reg‐

[75] Geliebter A, Gluck ME, Tanowitz M, et al. Work-shift period and weight change. Nu‐

[76] McAlpine DE, Frisch MJ, Romes ES, et al. Bariatric surgery: a primer for eating disor‐

[77] Sandberg RM, Dahl JK, Vedul-Kjelsas E, et al. Health-related quality of life in obese presurgery patients with and without binge eating disorder, and subdiagnostic binge

[78] Snyder, AG. Psychological assessment of the patient undergoing bariatric surgery.

[79] Kinzl JF, Schrattenecker M, Traweger C, et al. Psychosocial predictors of weight loss

[80] Chesler BE. Emotional eating: a virtually untreated risk factor for outcome following

[81] Thomas J, Gizis F, Marcus E. Food selections of Roux-en-Y gastric bypass patients up

[82] Timlin MT, Pereira MA. Breakfast frequency and quality in the etiology of obesity

[83] Pereira MA, Erickson E, McKee P. Breakfast frequency and quality may affect glyce‐

[84] Goldstone AP, Prechtl de Hernandez CG, Beaver JD, et al. Fasting biases brain re‐ ward systems towards high-calorie foods. Eur J Neurosci. 2009;30(8):1625-35.

[85] National Weight Control Registry. NWCR facts page. Available at: http:// www.nwcr.ws/Research/default.htm. Accessibility verified: November 1, 2013.

ting-factors-prevention. Accessed November 1, 2013.

scape of food deserts. Child Obes. 2012;8(1):28-30.

der professionals. Eur Eat Disord Rev. 2010;18(4):304-17.

after bariatric surgery. Obes Surg. 2006;16(12):1609-14.

bariatric surgery. ScienteificWorldJournal. 2012;2012:365961.

to 2.5 years postsurgery. J Am Diet Assoc. 2010;110(4):608-12.

and chronic diseases. Nutr Rev. 2007;65(6 Pt 1): 268-81.

mia in adults and children. J Nutr. 2011;141(1):163-8.

eating disorders. J Obes. 2013;2013:878310.

2010;110(4):571-84.

ul. 2013;47(3):159-70.

trition. 2000;16(1):27-29.

Oschner J. 2009;9(3):144-8.

[70] Aills L, Blankenship J, Buffington C, et al. ASMBS allied health nutritional guidelines for the surgical weight loss patient. Surg Obes Relat Dis. 2008;4(5 Suppl):S73-S108.

[55] Perna M, Romagnuolo J, Morgan K et al. Preoperative hemoglobin A1c and postop‐ erative glucose control in outcomes after gastric bypass for obesity. Surg Obes Relat

[56] National Institutes of Health. The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. http://www.nhlbi.nih.gov/guide‐

[57] Hampel H, Abraham NS, El-Serag HB. Meta-analysis: obesity and the risk for gastro‐ esophageal reflux disease and its complications. Ann Intern Med. 2005;143(3):

[58] Greenwald D. Preoperative gastrointestinal assessment before bariatric surgery. Gas‐

[59] Verma S, Sharma D, Kanwar P, et al. Prevalence of Helicobacter pylori infection in bariatric patients: a histologic assessment. Surg Obes Relat Dis. 2013;9(5):679-85.

[60] Rawlins L, Rawlins MP, Brown CC, Schumacher DL. Effect of Helicobacter pylori on marginal ulcer and stomal stenosis after roux-en-y gastric bypass. Surg Obes Relat

[61] World Health Organization. Global Burden of Disease – 2004 Update. Geneva, Swit‐

[62] Che F, Nguyen B, Cohen A, et al. Prevalence of hiatal hernia in the morbidly obese.

[63] Fris RJ. Preoperative low energy diet diminishes liver size. Obesity Surg.

[64] Edholm D, Kullberg J, Haenni A, et al. Preoperative 4-week low-calorie diet reduces liver volume and intrahepatic fat and facilitates laparoscopic gastric bypass in mor‐

[65] Guadalajara H, Sanz Boro R, Pascual I, et al. Is prophylactic cholecystectomy useful in obese patients undergoing gastric bypass? Obes Surg. 2006;16(7):883-5.

[66] Liem RK, Niloff PH. Prophylactic Cholecystectomy with open gastric bypass opera‐

[67] Hamad GG, Ikramuddin S, Gourash WF, et al. Elective cholecystectomy during lapa‐

[68] D'Hondt M, Sergeant G, Deylgat B, et al. Prophylactic cholecystectomy, a mandatory step in morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass? J

[69] Biesemeier CK, Garland J, eds. ADA Pocket Guide to Bariatric Surgery. Chicago, IL:

roscopic gastric bypass: is it worth the wait? Obesity Surg. 2003;13:76-81.

Surg Obes Relat Dis. 2013 Apr 19. Epub ahead of print

bidly obese. Obes Surg. 2011;21:345-50.

tion. Obes Surg. 2004;14:763-5.

Gastrointest Surg. 2011;15:1532-36.

American Dietetic Association; 2009.

lines/obesity/prctgd\_b.pdf. Accessed 10/26/2013.

troenterol Clin N Am. 2010;19;81-6.

Dis. 2012;6:686-90.

28 Essentials and Controversies in Bariatric Surgery

199-211.

Dis. 2013;9:760-4.

2004;14:1165-70.

zerland. WHO Press; 2008

[86] Centers for Disease Control. Overcoming barriers to physical activity page. Available at: http://www.cdc.gov/physicalactivity/everyone/getactive/barriers.html. Accessibil‐ ty verified: November 1, 2013.

[101] Kalarchian MA, Marcus MD, Levine MD, et al. Psychiatric disorders among bariatric surgery candidates: relationship to obesity and functional health status. Am j Psy‐

Preoperative Evaluation of Bariatric Surgery Patients

http://dx.doi.org/10.5772/58605

31

[102] Khan MA, Grinberg R, Johnson S, et al. Perioperative risk factors for 30-day mortality after bariatric surgery: is functional status important? Surg Endosc. 2013;27:1772-7.

[103] King WC, Bond DS. The importance of preoperative and postoperative physical ac‐ tivity counseling in bariatric surgery. Exerc Sport Sci Rev. 2013;41(1):26-35.

[104] American Society for Metabolic and Bariatric Surgery. ASMBS Public and Professio‐ nal Education Committee. Bariatric Surgery: Postoperative Concerns. http:// s3.amazonaws.com/publicASMBS/GuidelinesStatements/Guidelines/asbs\_bspc.pdf.

chiatry 2007; 164:328-34.

Accessed 10/28/2013.

[101] Kalarchian MA, Marcus MD, Levine MD, et al. Psychiatric disorders among bariatric surgery candidates: relationship to obesity and functional health status. Am j Psy‐ chiatry 2007; 164:328-34.

[86] Centers for Disease Control. Overcoming barriers to physical activity page. Available at: http://www.cdc.gov/physicalactivity/everyone/getactive/barriers.html. Accessibil‐

[87] Nicoletti CF, Lima TP, Donadelli SP, et al. New look at nutritional care for obese pa‐

[88] Schweiger C, Weiss R, Berry E, Keidar A. Nutritional deficiencies in bariatric surgery

[89] Germmel K, Santry HP, Prachand VN, Alverdy JC. Vitamin D deficiency in perioper‐

[90] Hoeft B, Weber P, Eggerdorfer M. Micronutrient – a global perspective on intake,

[91] Kaidar-Person O, Person B, Szomstein S, et al. Nutritional deficiencies in morbidly obese patients: a new form of malnutrition? Part A: vitamins. Obes Surg. 2008;18(7):

[92] Kaidar-Person O, Person B, Szomstein S, et al. Nutritional deficiencies in morbidly obese patients: a new form of malnutrition? Part B: minerals. Obes Surg. 2008;18(8):

[93] Kulick D, Hark L, Deen D. The bariatric surgery patient: a growing role for registered

[94] Kushner RF, Neff LM. Bariatric surgery: a key role for registered dietitians. J Am Diet

[95] Van Horn, L. The registered dietitian's role in treating bariatric surgery patients. J

[96] Heinberg LJ, Ashton K, Windover A. Moving beyond dichotomous psychological evaluation: the Cleveland Clinic Behavioral Rating System for weight loss surgery.

[97] Ambwani S, Boeka AG, Brown JD, et al. Socially desirable responding by bariatric surgery candidates during psychological assessment. Surg Obes Relat Dis.

[98] Simon GE, Von Korff M, Saunders K, et al. Association between obesity and psychi‐ atric disorders in the US adult population. Arch Gen Psychiatry. 2006;63:824-30.

[99] Greenberg I, Sogg S, Perna FM. Behavioral and psychological care in weight loss sur‐

[100] Goldstein N, Hadidi N. Impact of bariatric preoperative education on patient knowl‐ edge and satisfaction with overall hospital experience. Bariatr Nurs Surg Patient

tient candidates for bariatric surgery. Surg Obes Relat Dis. 2013;9:520-5.

ative bariatric surgery patients. Surg Obes Relat Dis. 2009;5:54-9.

health benefits and economics. Int J Nutr Res. 2012;82(5):312-20.

ty verified: November 1, 2013.

30 Essentials and Controversies in Bariatric Surgery

870-6

1028-34.

2013;9:300-5.

Care. 2010;5:137-44.

Assoc. 2010;110(4):524-6.

AM Diet Assoc. 2010;110(4):497.

Surg Obes Relat Dis. 2010;6:185-90.

gery: Best practice update. Obesity. 2009;17:880-4.

candidates. Obes Surg. 2010;20:193-7.

dietitians. J Am Diet Assoc. 2010;110(4):593-9.

**Chapter 2**

**Theoretical Bases and Dietary Approach of Bariatric**

Obesity ultimately results from an unbalance between the intake and oxidation of the energy obtained from foods, and its treatments are based on correcting this unbalance by basically restricting energy intake. Consequently, food intake is the center of attention when the subject

The inability of severely obese individuals to reduce or maintain their body weight using traditional methods makes them candidates to bariatric surgery, which is admittedly an effective method to reduce body weight significantly and obesity-associated morbidities. Bariatric surgery involves anatomic and physiological changes in the gastrointestinal tract that promote energy restriction, essential for weight loss, but also the restriction of many essential dietary nutrients. In addition to the anatomic aspects, bariatric surgery decreases appetite and increases postprandial satiety, possibly because of its effect on the secretion of hormones that

In addition to reducing body weight significantly, bariatric surgery also decreases some systemic inflammation markers (Chen et al., 2009; Miller et al., 2011), improves insulin sensitivity, promoting remission of type 2 diabetes (T2D), and lowers high blood pressure,

Although bariatric surgery is associated with better quality of life, nutritional deficiencies may occur after surgery because of the dramatically reduced food intake and/or micronutrient

> © 2014 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

is obesity, either as an etiological, protection, or even therapeutic factor.

Patrícia Fátima Sousa Novais, Flávia Andreia Marin,

Alex Harley Crisp, Irineu Rasera Junior,

Additional information is available at the end of the chapter

regulate these systems (Kohli, Stefater e Inge, 2011).

Celso Vieira de Souza Leite and Maria Rita Marques de Oliveira

http://dx.doi.org/10.5772/58636

**1. Introduction**

among others.

**Patients**

## **Theoretical Bases and Dietary Approach of Bariatric Patients**

Patrícia Fátima Sousa Novais, Flávia Andreia Marin, Alex Harley Crisp, Irineu Rasera Junior, Celso Vieira de Souza Leite and Maria Rita Marques de Oliveira

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/58636

**1. Introduction**

Obesity ultimately results from an unbalance between the intake and oxidation of the energy obtained from foods, and its treatments are based on correcting this unbalance by basically restricting energy intake. Consequently, food intake is the center of attention when the subject is obesity, either as an etiological, protection, or even therapeutic factor.

The inability of severely obese individuals to reduce or maintain their body weight using traditional methods makes them candidates to bariatric surgery, which is admittedly an effective method to reduce body weight significantly and obesity-associated morbidities. Bariatric surgery involves anatomic and physiological changes in the gastrointestinal tract that promote energy restriction, essential for weight loss, but also the restriction of many essential dietary nutrients. In addition to the anatomic aspects, bariatric surgery decreases appetite and increases postprandial satiety, possibly because of its effect on the secretion of hormones that regulate these systems (Kohli, Stefater e Inge, 2011).

In addition to reducing body weight significantly, bariatric surgery also decreases some systemic inflammation markers (Chen et al., 2009; Miller et al., 2011), improves insulin sensitivity, promoting remission of type 2 diabetes (T2D), and lowers high blood pressure, among others.

Although bariatric surgery is associated with better quality of life, nutritional deficiencies may occur after surgery because of the dramatically reduced food intake and/or micronutrient

© 2014 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

absorption. Unmonitored postoperative patients may develop severe malnutrition (Dodell et al., 2012). The literature has often reported deficiencies of vitamin B complex, iron, folic acid, vitamin D, and calcium (Saltzman e Karl, 2013). These deficiencies may cause neurological symptoms, osteopenia, and anemia.

are mostly malabsorptive reduce the intestinal absorption capacity significantly. BPD, for instance, decreases protein absorption by 25% and fat absorption by 72%, impairing the absorption of fat-soluble vitamins (Aills et al., 2008). BPD-DS lowers the serum concentration of thiamin in the first few months after surgery and of vitamins A and D one year after surgery

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

35

Today the main type of bariatric surgery done globally is RYGB, which reduces gastric capacity and causes a small degree of malabsorption as it bypasses the duodenum and a small part of the jejunum, namely, 30 centimeters of the proximal jejunum. Nevertheless, the bypassed segments can influence the absorption of proteins and some water-soluble vitamins, namely vitamins C, B1, B2, B6, and folic acid, absorbed in the proximal jejunum. Fat-soluble vitamins that require lipids to be absorbed may also be affected. Hence, mineral deficiencies in RYGB, such as Fe, Ca, and Zn stem from proximal small intestine bypass, specifically from duodenum

Vitamin and mineral deficiencies at first are asymptomatic or present unspecific symptoms. Laboratory tests are necessary to monitor and avoid the development of postoperative nutritional and clinical complications. Nutritional deficiencies found one year after surgery included Fe (51%), Ca and vitamin D (47%), folic acid (39%), and Zn (12%) (Gasteyger et al.,

Calcium and vitamin D deficiencies in obese patients in line for bariatric surgery are common, as well as high parathyroid hormone (PTH). Assessment of calcium metabolism should include measuring serum PTH, total calcium, phosphorus, 25-hydroxycholecalciferol, and the calcium present in 24 hours of urine. The normal levels of vitamin D, 25-hydroxycholecalciferol, or 25(OH)D range from 30 to 80 ng/mL. Vitamin D insufficiency occurs when these levels are below 30 but above 20ng/mL and deficiency when below 20ng/mL. The prevalences of vitamin D deficiency before and one year after RYGB were 86% and 70%, respectively (Signori et al., 2010). This deficiency may stem from inadequate intake and higher calcium and vitamin D requirements after surgery since the main calcium absorption sites are located in the bypassed intestinal section. Calcium, PTH, and vitamin D levels should be normalized before and after

In a sample of 30 female RYGB patients assessed eight years ago, Duran de Campos et al. (2008) found osteopenia (67%), osteoporosis (13%), low urine calcium (70%), vitamin D deficiency (90%), and high markers of bone metabolism, namely high PTH (54%) and high alkaline phosphatase (57%). Their mean calcium intake was roughly 50% of their daily requirement (1000mg), suggesting that bariatric patients should be encouraged to consume an

Iron deficiency is the main cause of anemia in bariatric patients. However, other nutrients associated with anemia are also malabsorbed, such as proteins and micronutrients required for iron metabolism and erythropoiesis, such as zinc, copper, folic acid, vitamin B12, and

more than RYGB does (Aasheim et al., 2009).

bypass.

2008).

**• Calcium and vitamin D**

surgery to avoid bone loss.

adequate amount of calcium.

**• Iron**

Hence, the nutritional approach of the bariatric patient, which began when the patient was in line for surgery and continued after surgery, is one of the most important themes of the interdisciplinary care of obese patients. The objective of this chapter is to review the theoretical bases for the nutritional approach of bariatric patients, the instruments for assessing food intake, and the nutritional recommendations, both preoperatively, when the patient is preparing for surgery, and postoperatively, during follow-up. The chapter also includes practical examples.

## **2. The nutrition process after bariatric surgery**

The surgeries used for treating severe obesity include restrictive surgeries that limit food intake, such as vertical banded gastroplasty (VBG), adjustable gastric band (AGB), and sleeve gastrectomy (SG); and mixed surgeries that combine food intake restriction with nutrient malabsorption, such as Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD) with duodenal switch (BPD-DS) (Pories, 2008).

The implications of surgery on nutritional status stem specifically from the types of anatomic and physiological changes the surgery makes. The main macro-and micronutrient absorption sites reflect the dimension of the nutritional impairment, especially in the long run, and the possible nutritional complications promoted by bariatric surgery, a situation that should be prevented with appropriate monitoring and supplementation.

In restrictive surgeries, nutritional deficiencies are associated with inadequate food intake, while in malabsorptive interventions, deficiencies are more associated with the hindrance of nutrient digestion and absorption. In summary, the energy deficit caused by low macronu‐ trient intake and/or absorption is accompanied by inadequate intake of essential nutrients.

The small intestine, target of the bypasses associated with malabsorptive techniques, is where most of food digestion and absorption occurs. The absorption of iron (Fe), calcium (Ca), zinc (Zn), selenium (Se), copper (Cu), and some water-soluble vitamins, such as vitamin C, thiamin (B1), and riboflavin (B2) occurs in the duodenum; the absorption of Fe, Zn, chromium, amino acids, peptides, carbohydrates, lipids, the fat-soluble vitamins A, D, E, and K, and most of the water-soluble vitamins occurs in the jejunum; and the absorption of amino acids, peptides, lipids, fat-soluble vitamins, magnesium, vitamin B12, and folic acid occurs in the ileum. Generally, the most common micronutrient deficiencies after bariatric surgery are Fe, Ca, vitamin D, vitamin B12, folic acid, and Zn (Bloomberg et al., 2005).

In BPD associated with gastrectomy, mostly a malabsorptive mixed surgery, nutrient malab‐ sorption is even greater, causing massive nutrient loss. Nutrient malabsorption is one of the factors that explain weight loss promoted by malabsorptive techniques, but techniques that are mostly malabsorptive reduce the intestinal absorption capacity significantly. BPD, for instance, decreases protein absorption by 25% and fat absorption by 72%, impairing the absorption of fat-soluble vitamins (Aills et al., 2008). BPD-DS lowers the serum concentration of thiamin in the first few months after surgery and of vitamins A and D one year after surgery more than RYGB does (Aasheim et al., 2009).

Today the main type of bariatric surgery done globally is RYGB, which reduces gastric capacity and causes a small degree of malabsorption as it bypasses the duodenum and a small part of the jejunum, namely, 30 centimeters of the proximal jejunum. Nevertheless, the bypassed segments can influence the absorption of proteins and some water-soluble vitamins, namely vitamins C, B1, B2, B6, and folic acid, absorbed in the proximal jejunum. Fat-soluble vitamins that require lipids to be absorbed may also be affected. Hence, mineral deficiencies in RYGB, such as Fe, Ca, and Zn stem from proximal small intestine bypass, specifically from duodenum bypass.

Vitamin and mineral deficiencies at first are asymptomatic or present unspecific symptoms. Laboratory tests are necessary to monitor and avoid the development of postoperative nutritional and clinical complications. Nutritional deficiencies found one year after surgery included Fe (51%), Ca and vitamin D (47%), folic acid (39%), and Zn (12%) (Gasteyger et al., 2008).

#### **• Calcium and vitamin D**

absorption. Unmonitored postoperative patients may develop severe malnutrition (Dodell et al., 2012). The literature has often reported deficiencies of vitamin B complex, iron, folic acid, vitamin D, and calcium (Saltzman e Karl, 2013). These deficiencies may cause neurological

Hence, the nutritional approach of the bariatric patient, which began when the patient was in line for surgery and continued after surgery, is one of the most important themes of the interdisciplinary care of obese patients. The objective of this chapter is to review the theoretical bases for the nutritional approach of bariatric patients, the instruments for assessing food intake, and the nutritional recommendations, both preoperatively, when the patient is preparing for surgery, and postoperatively, during follow-up. The chapter also includes

The surgeries used for treating severe obesity include restrictive surgeries that limit food intake, such as vertical banded gastroplasty (VBG), adjustable gastric band (AGB), and sleeve gastrectomy (SG); and mixed surgeries that combine food intake restriction with nutrient malabsorption, such as Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD)

The implications of surgery on nutritional status stem specifically from the types of anatomic and physiological changes the surgery makes. The main macro-and micronutrient absorption sites reflect the dimension of the nutritional impairment, especially in the long run, and the possible nutritional complications promoted by bariatric surgery, a situation that should be

In restrictive surgeries, nutritional deficiencies are associated with inadequate food intake, while in malabsorptive interventions, deficiencies are more associated with the hindrance of nutrient digestion and absorption. In summary, the energy deficit caused by low macronu‐ trient intake and/or absorption is accompanied by inadequate intake of essential nutrients. The small intestine, target of the bypasses associated with malabsorptive techniques, is where most of food digestion and absorption occurs. The absorption of iron (Fe), calcium (Ca), zinc (Zn), selenium (Se), copper (Cu), and some water-soluble vitamins, such as vitamin C, thiamin (B1), and riboflavin (B2) occurs in the duodenum; the absorption of Fe, Zn, chromium, amino acids, peptides, carbohydrates, lipids, the fat-soluble vitamins A, D, E, and K, and most of the water-soluble vitamins occurs in the jejunum; and the absorption of amino acids, peptides, lipids, fat-soluble vitamins, magnesium, vitamin B12, and folic acid occurs in the ileum. Generally, the most common micronutrient deficiencies after bariatric surgery are Fe, Ca,

In BPD associated with gastrectomy, mostly a malabsorptive mixed surgery, nutrient malab‐ sorption is even greater, causing massive nutrient loss. Nutrient malabsorption is one of the factors that explain weight loss promoted by malabsorptive techniques, but techniques that

symptoms, osteopenia, and anemia.

34 Essentials and Controversies in Bariatric Surgery

**2. The nutrition process after bariatric surgery**

prevented with appropriate monitoring and supplementation.

vitamin D, vitamin B12, folic acid, and Zn (Bloomberg et al., 2005).

with duodenal switch (BPD-DS) (Pories, 2008).

practical examples.

Calcium and vitamin D deficiencies in obese patients in line for bariatric surgery are common, as well as high parathyroid hormone (PTH). Assessment of calcium metabolism should include measuring serum PTH, total calcium, phosphorus, 25-hydroxycholecalciferol, and the calcium present in 24 hours of urine. The normal levels of vitamin D, 25-hydroxycholecalciferol, or 25(OH)D range from 30 to 80 ng/mL. Vitamin D insufficiency occurs when these levels are below 30 but above 20ng/mL and deficiency when below 20ng/mL. The prevalences of vitamin D deficiency before and one year after RYGB were 86% and 70%, respectively (Signori et al., 2010). This deficiency may stem from inadequate intake and higher calcium and vitamin D requirements after surgery since the main calcium absorption sites are located in the bypassed intestinal section. Calcium, PTH, and vitamin D levels should be normalized before and after surgery to avoid bone loss.

In a sample of 30 female RYGB patients assessed eight years ago, Duran de Campos et al. (2008) found osteopenia (67%), osteoporosis (13%), low urine calcium (70%), vitamin D deficiency (90%), and high markers of bone metabolism, namely high PTH (54%) and high alkaline phosphatase (57%). Their mean calcium intake was roughly 50% of their daily requirement (1000mg), suggesting that bariatric patients should be encouraged to consume an adequate amount of calcium.

#### **• Iron**

Iron deficiency is the main cause of anemia in bariatric patients. However, other nutrients associated with anemia are also malabsorbed, such as proteins and micronutrients required for iron metabolism and erythropoiesis, such as zinc, copper, folic acid, vitamin B12, and vitamin A. Specifically, iron deficiency may stem from three events: 1) less dietary iron, especially heme iron present in meats; 2) less hydrochloric acid because of the stomach bypass, which reduces the dissolution of iron salts; and 3) duodenum bypass, given that the duodenum is the main site of iron absorption (Ruz et al. 2009).

physiological changes, bariatric surgery promotes hormonal changes, such as reducing ghrelin production in the fundus of the stomach (an important endogenous orexigenic) and increasing intestinal hormones, namely peptide YY, glucagon-like peptide-1 (GLP-1), and gastric inhibitory polypeptide (GIP). The presence of poorly digested food in the distal small intestine after RYGB and BPD seem to stimulate the production of gut hormones, increasing incretins, GLP-1, and GIP, which help to control postoperative weight and glycemia (Rodieux et al., 2008). GLP-1 has a significant postprandial incretin effect, affecting insulin secretion, modu‐ lating appetite and gastric emptying, and eventually impacting the capture of glucose by tissues. Although some studies emphasize the role of lower serum ghrelin and higher incretin on satiety and weight control, other studies have not ultimately confirmed that hunger, satiety, and weight loss are related to these hormonal changes, so more studies are needed (Heber et

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

37

Although obesity is caused by an intake of macronutrients in excess of the body's requirement, certain nutrient deficiencies are often present in obese individuals. High intake of processed, energy-dense foods of usually poor nutritional value contributes significantly to micronutrient deficiencies. Additionally, an increase in adiposity and consequent oxidative stress may reduce the levels of some fat-soluble vitamins and nonenzymatic antioxidants. As a matter of fact, population data have shown that micronutrient inadequacy is greater among overweight and

Patients in the waiting line for bariatric surgery have a high to moderate prevalence of the following deficiencies: calcium (Jastrzębska-Mierzyńska et al., 2012), folic acid (Schweiger et al., 2010; Jastrzębska-Mierzyńska et al., 2012; de Luis et al., 2013), iron (Flancbaum et al., 2006; Schweiger et al., 2010; Jastrzębska-Mierzyńska et al., 2012), vitamin A (Nicoletti et al., 2013), vitamin C (Aasheim et al., 2008; Nicoletti et al., 2013), vitamin E (Aasheim et al., 2008), vitamin B1 (Flancbaum et al., 2006), vitamin B<sup>6</sup> (Aasheim et al., 2008; Moizé et al., 2011;), vitamin B12 (Ernst et al., 2009; Nicoletti et al., 2013), magnesium (Moizé et al., 2011; Nicoletti et al., 2013), copper (de Luis et al., 2013), and zinc (Ernst et al., 2009; de Luis et al., 2013). The prevalence of anemia is also moderate to high (Flancbaum et al., 2006; Schweiger et al., 2010; Moizé et al., 2011).

Vitamin D is a fat-soluble vitamin with hormonal functions. It acts on many tissues especially through nuclear and membrane receptors. Evidence shows that vitamin D is essential for bone mineralization and acts on the pancreas, immune system, and nervous system, among others. Low vitamin D in obese individuals may be related to low dietary bioavailability, inadequate sunlight exposure, and even sequestration by adipose tissue (Brouwer et al., 1998). Some studies report a low to moderate inverse correlation between serum vitamin D and body mass

**3. The nutritional needs of obese and ex-obese individuals**

al., 2010).

obese adults (Kimmons et al., 2006).

The prevalence of anemia in bariatric patients varies according to time elapsed since surgery, type of surgery, and sex, with women of childbearing age being more vulnerable. In a prospective study of 1125 RYGB patients of which 999 were females, Drygalski et al. (2011) found a prevalence of anemia of 12% six months after surgery, which increased to 21% eighteen months after surgery and 23% one to two years after surgery. Six months after surgery, the prevalence of anemia in menopausal women was 6% against 16% in premenopausal women.

## **• Vitamin B12**

The absorption of vitamin B12 is also impaired by gastric restriction, a procedure performed in restrictive, mixed, and mostly malabsorptive surgeries. Although the absorption of vitamin B12 occurs in the terminal ileum, B12 can only be absorbed when bound to an intrinsic factor, a glycoprotein produced by parietal cells, in the presence of hydrochloric acid and pepsin. These molecular interactions usually occur in the distal stomach and duodenum, and RYGB bypasses both (Flancbaum et al., 2006).

Vitamin B12 deficiency is common: 33-40% of the patients develop it one year after RYGB (Brolin et al., 2002). A study found that RYGB patients taking conventional nutrient supple‐ mentation still developed B12 deficiency and required further supplementation. The most common deficiency was of vitamin B12: 62% and 80% of the patients had it one and two years after surgery, respectively. A combined deficiency of vitamin B12 and folic acid may cause megaloblastic anemia (Heber et al., 2010). Other studies have reported that conventional supplementation is enough to prevent folic acid deficiency. In addition to the dosages present in multivitamins, our patients take a quarterly injection of Citoneurin 5000UI, rich in B complex.

## **• Generality**

Deficiencies present preoperatively, such as iron (44%), vitamin D (68%), and thiamin (29%) deficiencies (Flancbaum et al., 2006), may worsen after surgery, but few studies have investi‐ gated how preoperative deficiencies relate to postoperative nutritional complications, another theme requiring further investigation. Another particularity that deserves attention regards iron, since preoperative deficiency may not be exclusively nutritional: the inflammation associated with obesity hinders the regulation of iron metabolism, promoting the development of functional iron deficiency. Iron homeostasis is regulated by hepcidin, a circulating peptide hormone produced mainly by hepatocytes but also by adipocytes, which acts as a negative regulator of iron metabolism (Bekri et al., 2006). Studies grouping these two situations, preoperative functional deficiency and postoperative iron levels, may clarify current perspec‐ tives and establish new ones on iron supplementation.

The significant changes made by bariatric surgery reduce energy intake and intestinal absorptive capacity, factors that contribute to weight loss. In addition to the anatomic and physiological changes, bariatric surgery promotes hormonal changes, such as reducing ghrelin production in the fundus of the stomach (an important endogenous orexigenic) and increasing intestinal hormones, namely peptide YY, glucagon-like peptide-1 (GLP-1), and gastric inhibitory polypeptide (GIP). The presence of poorly digested food in the distal small intestine after RYGB and BPD seem to stimulate the production of gut hormones, increasing incretins, GLP-1, and GIP, which help to control postoperative weight and glycemia (Rodieux et al., 2008). GLP-1 has a significant postprandial incretin effect, affecting insulin secretion, modu‐ lating appetite and gastric emptying, and eventually impacting the capture of glucose by tissues. Although some studies emphasize the role of lower serum ghrelin and higher incretin on satiety and weight control, other studies have not ultimately confirmed that hunger, satiety, and weight loss are related to these hormonal changes, so more studies are needed (Heber et al., 2010).

## **3. The nutritional needs of obese and ex-obese individuals**

vitamin A. Specifically, iron deficiency may stem from three events: 1) less dietary iron, especially heme iron present in meats; 2) less hydrochloric acid because of the stomach bypass, which reduces the dissolution of iron salts; and 3) duodenum bypass, given that the duodenum

The prevalence of anemia in bariatric patients varies according to time elapsed since surgery, type of surgery, and sex, with women of childbearing age being more vulnerable. In a prospective study of 1125 RYGB patients of which 999 were females, Drygalski et al. (2011) found a prevalence of anemia of 12% six months after surgery, which increased to 21% eighteen months after surgery and 23% one to two years after surgery. Six months after surgery, the prevalence of anemia in menopausal women was 6% against 16% in premenopausal women.

The absorption of vitamin B12 is also impaired by gastric restriction, a procedure performed in restrictive, mixed, and mostly malabsorptive surgeries. Although the absorption of vitamin B12 occurs in the terminal ileum, B12 can only be absorbed when bound to an intrinsic factor, a glycoprotein produced by parietal cells, in the presence of hydrochloric acid and pepsin. These molecular interactions usually occur in the distal stomach and duodenum, and RYGB

Vitamin B12 deficiency is common: 33-40% of the patients develop it one year after RYGB (Brolin et al., 2002). A study found that RYGB patients taking conventional nutrient supple‐ mentation still developed B12 deficiency and required further supplementation. The most common deficiency was of vitamin B12: 62% and 80% of the patients had it one and two years after surgery, respectively. A combined deficiency of vitamin B12 and folic acid may cause megaloblastic anemia (Heber et al., 2010). Other studies have reported that conventional supplementation is enough to prevent folic acid deficiency. In addition to the dosages present in multivitamins, our patients take a quarterly injection of Citoneurin 5000UI, rich in B

Deficiencies present preoperatively, such as iron (44%), vitamin D (68%), and thiamin (29%) deficiencies (Flancbaum et al., 2006), may worsen after surgery, but few studies have investi‐ gated how preoperative deficiencies relate to postoperative nutritional complications, another theme requiring further investigation. Another particularity that deserves attention regards iron, since preoperative deficiency may not be exclusively nutritional: the inflammation associated with obesity hinders the regulation of iron metabolism, promoting the development of functional iron deficiency. Iron homeostasis is regulated by hepcidin, a circulating peptide hormone produced mainly by hepatocytes but also by adipocytes, which acts as a negative regulator of iron metabolism (Bekri et al., 2006). Studies grouping these two situations, preoperative functional deficiency and postoperative iron levels, may clarify current perspec‐

The significant changes made by bariatric surgery reduce energy intake and intestinal absorptive capacity, factors that contribute to weight loss. In addition to the anatomic and

is the main site of iron absorption (Ruz et al. 2009).

36 Essentials and Controversies in Bariatric Surgery

bypasses both (Flancbaum et al., 2006).

tives and establish new ones on iron supplementation.

**• Vitamin B12**

complex.

**• Generality**

Although obesity is caused by an intake of macronutrients in excess of the body's requirement, certain nutrient deficiencies are often present in obese individuals. High intake of processed, energy-dense foods of usually poor nutritional value contributes significantly to micronutrient deficiencies. Additionally, an increase in adiposity and consequent oxidative stress may reduce the levels of some fat-soluble vitamins and nonenzymatic antioxidants. As a matter of fact, population data have shown that micronutrient inadequacy is greater among overweight and obese adults (Kimmons et al., 2006).

 The prevalence of anemia is also moderate to high (Flancbaum et al., 2006; Schweiger et al., 2010; Moizé et al., 2011).

Vitamin D is a fat-soluble vitamin with hormonal functions. It acts on many tissues especially through nuclear and membrane receptors. Evidence shows that vitamin D is essential for bone mineralization and acts on the pancreas, immune system, and nervous system, among others. Low vitamin D in obese individuals may be related to low dietary bioavailability, inadequate sunlight exposure, and even sequestration by adipose tissue (Brouwer et al., 1998). Some studies report a low to moderate inverse correlation between serum vitamin D and body mass index (Parikn et al., 2004; Carlin et al., 2005; McGil et al., 2008; Cimbek et al., 2012; Taheri et al., 2012).

also err because of the use of standard recipes and data variation in food composition tables

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

39

The food intake assessment of obese patients consists of many challenges, such as obtaining reliable information, identifying underreporting, correctly estimating energy and nutrient

A common finding in studies that assess the food intake of obese individuals is low energy intake, which may stem from food intake underreporting and/or physical activity overreport‐ ing (Macdiarmid; Blundell, 1998; Lichtman et al., 1992). Individual characteristics associated with underreporting include being older, female, and physically inactive; having low social and educational levels; restricting foods; experiencing emotional changes (Abbot et al., 2008; Macdiarmid; Blundell, 1998); and especially, having a high body mass index, that is, being

The classification of individuals as underreporters is based on the premise that individuals in energy balance, that is, whose weights are constant, have equivalent energy intake and expenditure (Goldberg et al., 1991; Trabulsi; Schoeller, 2001). Energy intake determined by quantitative survey can be confirmed by doubly labeled water (DLW), which accurately measures total energy expenditure (TEE) (Schoeller, 1999). The energy intake reported in food intake assessments is usually much lower than the actual energy intake (Black, Cole, 2001).

A review of DLW and calorimetry studies treated the intra-and interindividual energy intake variations statistically to establish the cutoff points that identify the lowest, plausible energy intake levels and expressed them as multiples of the resting energy expenditure (REE) (Goldberg et al., 1991). The TEE:REE ratio is known as the physical activity level (PAL). In energy balance, reported energy intake (EIrep) divided by REE should be equal to the TEE divided by REE, that is, EIrep:REE=TEE:REE or EIrep:REE=PAL. Many adjustments have been proposed to maximize the sensitivity and specificity of the cutoff point. Different studies have replaced variables of the Goldberg's equation, one at a time, by constants (Black, 2000), especially PAL, sample size, and number of food intake assessments (Black et al., 1991; Black, 2000; Goldberg et al., 1991; Abbot et al., 2008). Our research group Quesada (2011) used the Goldberg's equation in six different ways to classify the underreporting of 100 morbidly obese women. The prevalence of underreporting varied significantly, from 43% to 92%. This difference stemmed mainly from the intraindividual variations of the study sample, namely PAL and sample size, which minimized the underreporting interpretation error when used in

Nowadays studies tend to investigate food pattern, as opposed to individual nutrients, to establish relationships between diet and the health statuses of intragroup individuals (Hu, 2002). Dietary pattern analysis characterizes the eating behavior of population groups, elucidating the association between diet and health and/or other factors (Moeller et al., 2007). Dietary patterns characterized by the intake of fruits, vegetables, whole grains, fish, and poultry have been associated with a high intake of micronutrients and with selected biomark‐

ers of dietary exposure and disease risk in the expected direction (Kant, 2004).

requirements, and establishing the appropriate interventions (Anjos et al., 2009).

overweight or obese (Rennie, Coward, Jebb, 2007; Scagliusi et al, 2009).

(Dodd et al., 2006).

the equation.

 These differences may stem from different food habits, which vary between cities, states, and countries. Therefore, nutritional assessment by laboratory tests and food surveys is strongly recommended to detect nutritional insufficiencies early and make the necessary nutritional interventions. Symptoms caused by undetected preexisting deficiencies may become worse during the postoperative period. Since biochemical tests are expensive, Mechanick et al., (2013) suggest starting micronutrient supplementation in the preoperative period.

Gastric surgery is essential for promoting energy intake restriction and consequently, energy deficit and weight loss. Nonetheless, this procedure may induce strong aversion to certain foods, malnutrition, and specific micronutrient deficiencies. Recently, the American Associa‐ tion of Clinical Endocrinologists, The Obesity Society and the American Society for Metabolic & Bariatric Surgery (Mechanick et al., 2013) published the nutritional requirements of ex-obese bariatric patients. In summary, these individuals should take multivitamin and multimineral supplements that help them to meet their daily requirements of the main micronutrients (elemental calcium: 1200-1500 mg; vitamin D: 3000 IU; vitamin B12: 1000 mcg; folic acid: 400 μg; iron: 45-60 mg) and protein (1.5 grams (60g/d) per kilogram of body weight).

## **4. Food intake assessment**

Determining food intake is a constant challenge for the science and practice of nutrition and dietetics. Food surveys indirectly assess nutritional status. They are always under scrutiny because of their limited ability to measure energy and nutrient intakes. Quantitative and qualitative food intake can be determined by different methods, such as recalls, in which individuals remember the foods they ate. The most important of these retrospective methods are the food frequency questionnaire (FFQ) and the 24-hour recall (24HR). Food intake may also be investigated prospectively by asking individuals to write down the foods they eat in a food diary or record (FD) the moment they eat them (Gibson, 2005; Anjos et al., 2009).

The food intake survey of choice depends on the study objectives and population, but administering a single 24HR or FD to assess habitual food intake is not recommended, not even for obese individuals. Intraindividual variations, that is, daily variations in food intake, occur, so at least two surveys should be administered on alternate days. Some studies recommend three 24HR or FD administered on alternate days, including a weekend day (Johnson, 2002), which allows statistical adjustment of the variances of the study days' mean. Some factors may distort food intake data, such as the interviewer's skill, interviewee's memory, and interview's environment. Moreover, the assessment itself may affect an indi‐ vidual's intake pattern and consequently, information quality. Nutrient intake estimates may also err because of the use of standard recipes and data variation in food composition tables (Dodd et al., 2006).

index (Parikn et al., 2004; Carlin et al., 2005; McGil et al., 2008; Cimbek et al., 2012; Taheri et

The prevalences of micronutrient deficiencies vary between studies (Flancbaum et al., 2006; Carlin et al., 2006; Aasheim et al., 2008; Toh, Zarshenas, Jorgensen, 2009; Gammel et al., 2009; Fish et al., 2010; Casagrande et al., 2010; Ducloux et al., 2011; Moizé et al., 2011; Jastrzębska-Mierzyńska et al., 2012; de Luis et al., 2013; Censani et al., 2013). These differences may stem from different food habits, which vary between cities, states, and countries. Therefore, nutritional assessment by laboratory tests and food surveys is strongly recommended to detect nutritional insufficiencies early and make the necessary nutritional interventions. Symptoms caused by undetected preexisting deficiencies may become worse during the postoperative period. Since biochemical tests are expensive, Mechanick et al., (2013) suggest starting

Gastric surgery is essential for promoting energy intake restriction and consequently, energy deficit and weight loss. Nonetheless, this procedure may induce strong aversion to certain foods, malnutrition, and specific micronutrient deficiencies. Recently, the American Associa‐ tion of Clinical Endocrinologists, The Obesity Society and the American Society for Metabolic & Bariatric Surgery (Mechanick et al., 2013) published the nutritional requirements of ex-obese bariatric patients. In summary, these individuals should take multivitamin and multimineral supplements that help them to meet their daily requirements of the main micronutrients (elemental calcium: 1200-1500 mg; vitamin D: 3000 IU; vitamin B12: 1000 mcg; folic acid: 400

Determining food intake is a constant challenge for the science and practice of nutrition and dietetics. Food surveys indirectly assess nutritional status. They are always under scrutiny because of their limited ability to measure energy and nutrient intakes. Quantitative and qualitative food intake can be determined by different methods, such as recalls, in which individuals remember the foods they ate. The most important of these retrospective methods are the food frequency questionnaire (FFQ) and the 24-hour recall (24HR). Food intake may also be investigated prospectively by asking individuals to write down the foods they eat in a food diary or record (FD) the moment they eat them (Gibson, 2005; Anjos et al., 2009).

The food intake survey of choice depends on the study objectives and population, but administering a single 24HR or FD to assess habitual food intake is not recommended, not even for obese individuals. Intraindividual variations, that is, daily variations in food intake, occur, so at least two surveys should be administered on alternate days. Some studies recommend three 24HR or FD administered on alternate days, including a weekend day (Johnson, 2002), which allows statistical adjustment of the variances of the study days' mean. Some factors may distort food intake data, such as the interviewer's skill, interviewee's memory, and interview's environment. Moreover, the assessment itself may affect an indi‐ vidual's intake pattern and consequently, information quality. Nutrient intake estimates may

μg; iron: 45-60 mg) and protein (1.5 grams (60g/d) per kilogram of body weight).

micronutrient supplementation in the preoperative period.

**4. Food intake assessment**

al., 2012).

38 Essentials and Controversies in Bariatric Surgery

The food intake assessment of obese patients consists of many challenges, such as obtaining reliable information, identifying underreporting, correctly estimating energy and nutrient requirements, and establishing the appropriate interventions (Anjos et al., 2009).

A common finding in studies that assess the food intake of obese individuals is low energy intake, which may stem from food intake underreporting and/or physical activity overreport‐ ing (Macdiarmid; Blundell, 1998; Lichtman et al., 1992). Individual characteristics associated with underreporting include being older, female, and physically inactive; having low social and educational levels; restricting foods; experiencing emotional changes (Abbot et al., 2008; Macdiarmid; Blundell, 1998); and especially, having a high body mass index, that is, being overweight or obese (Rennie, Coward, Jebb, 2007; Scagliusi et al, 2009).

The classification of individuals as underreporters is based on the premise that individuals in energy balance, that is, whose weights are constant, have equivalent energy intake and expenditure (Goldberg et al., 1991; Trabulsi; Schoeller, 2001). Energy intake determined by quantitative survey can be confirmed by doubly labeled water (DLW), which accurately measures total energy expenditure (TEE) (Schoeller, 1999). The energy intake reported in food intake assessments is usually much lower than the actual energy intake (Black, Cole, 2001).

A review of DLW and calorimetry studies treated the intra-and interindividual energy intake variations statistically to establish the cutoff points that identify the lowest, plausible energy intake levels and expressed them as multiples of the resting energy expenditure (REE) (Goldberg et al., 1991). The TEE:REE ratio is known as the physical activity level (PAL). In energy balance, reported energy intake (EIrep) divided by REE should be equal to the TEE divided by REE, that is, EIrep:REE=TEE:REE or EIrep:REE=PAL. Many adjustments have been proposed to maximize the sensitivity and specificity of the cutoff point. Different studies have replaced variables of the Goldberg's equation, one at a time, by constants (Black, 2000), especially PAL, sample size, and number of food intake assessments (Black et al., 1991; Black, 2000; Goldberg et al., 1991; Abbot et al., 2008). Our research group Quesada (2011) used the Goldberg's equation in six different ways to classify the underreporting of 100 morbidly obese women. The prevalence of underreporting varied significantly, from 43% to 92%. This difference stemmed mainly from the intraindividual variations of the study sample, namely PAL and sample size, which minimized the underreporting interpretation error when used in the equation.

Nowadays studies tend to investigate food pattern, as opposed to individual nutrients, to establish relationships between diet and the health statuses of intragroup individuals (Hu, 2002). Dietary pattern analysis characterizes the eating behavior of population groups, elucidating the association between diet and health and/or other factors (Moeller et al., 2007). Dietary patterns characterized by the intake of fruits, vegetables, whole grains, fish, and poultry have been associated with a high intake of micronutrients and with selected biomark‐ ers of dietary exposure and disease risk in the expected direction (Kant, 2004).

The association of one or a few nutrients with a given disease has conceptual and methodo‐ logical limitations (Hu, 2002). These limitations are evidenced by the fact that they do not take into account the complex synergy between dietary nutrients, the cumulative effects and multiple nutrients that compose dietary patterns, the statistical significance that a wide range of chemical elements or foods can produce, and the relationship of association between the intake of certain nutrients and dietary patterns (Moeller et al., 2007). Hence, dietary pattern analysis has emerged as an alternative and complementary approach in nutritional epidemio‐ logical studies that evidence the relationship between the overall diet and the risk of chronic diseases (Hu, 2002).

the importance of adhering to the dietary recommendations because of the anatomical and

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

41

Once the type of surgery is selected, patients should undergo a nutritional assessment as soon as possible to identify possible nutritional deficiencies, establish a plan to promote dietary adequacy, and make sure they understand the dietary changes they will experience to prevent postoperative complications. Factors such as the patient's readiness for change, realistic expectations, general food and nutrition knowledge, and financial aspects must be investigat‐

Planning the nutritional intervention requires defining treatment objectives. Goals are individual and based on associated diseases, personal preferences, and habits mentioned in the nutritional anamnesis. Weight loss maintenance demands the adoption of proper food

The preoperative nutritional approach may be collective or individual. We conduct a complete nutritional anamnesis in our first meeting with the patients and seize the opportunity to help them to improve their dietary habits, bond with them, destroy misconceptions and myths, and inform them about the surgery and the necessary postoperative dietary changes required by

Nutritional anamnesis has a critical role in nutrition and health research. Its objective is to characterize the general nutritional status of an individual to determine the appropriate

**•** Anthropometric assessment: preoperative weight, height, body mass index (BMI=kg/m2

percentage of excess weight (%), and body composition determined by bioelectrical

**•** History of weight and previous treatments: patients are asked about the details of their obesity history, unsuccessful weight loss treatments, life events that may have promoted

**•** Biochemical parameters: includes the tests routinely requested by the surgeon and endo‐ crinologist during the preoperative period as recommended by the Brazilian Society of Bariatric and Metabolic Surgery and American Society for Metabolic & Bariatric Surgery; **•** Clinical history: assesses the patients' comorbidities and the drugs and supplements they are taking and verifies the presence of orthodontic and sight problems and of food allergies.

Bowel movements, voiding habits, and menstrual frequency are also investigated;

**•** Smoking: the patients are asked about their smoking habits, including the number of

weight changes, weight loss expectations, and previous clinical treatments;

),

hormonal changes, and the resultant biopsychosocial and physical activity changes.

ed and clarified during the preoperative nutritional treatment.

the surgery of choice.

intervention.

*5.1.1. Nutritional anamnesis*

Anamnesis consists of:

impedance analysis;

cigarettes consumed per day;

**5.1. Initial interventions and strategies for preoperative weight loss**

choice-related habits and practices, eating behaviors, and energy expenditure.

Multivariate statistical analyses have been used for defining dietary patterns. Factor analysis, which includes both principal component analysis (PCA) and factorial analysis, is a multi‐ variate statistical technique that uses food intake data to identify common subjacent dietary factors or patterns (Hu, 2002; Moeller et al., 2007). Cluster analysis, another multivariate method, aggregates individuals into relatively homogeneous subgroups with similar dietary characteristics. These techniques allow the classification of individuals into distinct groups or in groups according to food intake frequency; classification of foods or food groups according to their percentage energy contribution or mean amount consumed in grams; establishment of nutrient intake patterns; and combination of dietary and biochemical measurements (Hu, 2002; Moeller et al., 2007).

The association between dietary pattern and the prevalence of obesity and/or cardiovascular diseases has indicated a positive correlation between certain dietary patterns and indicators of these diseases (Berg et al., 2009; Howarth et al., 2007; Ma et al., 2003; Meyer et al., 2011; Newby et al., 2003; Neumann et al., 2007; Sherafat-kazemzadeh et al., 2010; Sichieri, 2002). Nevertheless, reviews on dietary patterns and their relationship with certain diseases have found data inconsistencies, signaling the need of more thorough studies on this theme (Bhupathiraju; Tucker, 2011; Kant, 2004; Togo et al., 2001).

Based on the high frequency of food intake underreporting among the obese, some food groups and/or nutrients in the dietary patterns of obese women classified as energy intake underre‐ porters may vary, so more studies are needed to identify the intake particularities of this population. In our group, Ravelli (2013) found that women often underreported their energy intake and that underreporting was associated with a healthier dietary pattern than the pattern of women who reported their intake correctly. This suggests that underreporting involves foods that obese individuals should restrict.

## **5. Dietary approach of preoperative patients**

The objective of bariatric surgery is to reduce energy intake and consequently promote weight loss, better quality of life, and the improvement of associated comorbidities. Long-term weight loss maintenance depends on the development of a multidisciplinary education program focusing on the surgery, making patients and family members aware of its risks and benefits, the importance of adhering to the dietary recommendations because of the anatomical and hormonal changes, and the resultant biopsychosocial and physical activity changes.

Once the type of surgery is selected, patients should undergo a nutritional assessment as soon as possible to identify possible nutritional deficiencies, establish a plan to promote dietary adequacy, and make sure they understand the dietary changes they will experience to prevent postoperative complications. Factors such as the patient's readiness for change, realistic expectations, general food and nutrition knowledge, and financial aspects must be investigat‐ ed and clarified during the preoperative nutritional treatment.

## **5.1. Initial interventions and strategies for preoperative weight loss**

Planning the nutritional intervention requires defining treatment objectives. Goals are individual and based on associated diseases, personal preferences, and habits mentioned in the nutritional anamnesis. Weight loss maintenance demands the adoption of proper food choice-related habits and practices, eating behaviors, and energy expenditure.

The preoperative nutritional approach may be collective or individual. We conduct a complete nutritional anamnesis in our first meeting with the patients and seize the opportunity to help them to improve their dietary habits, bond with them, destroy misconceptions and myths, and inform them about the surgery and the necessary postoperative dietary changes required by the surgery of choice.

#### *5.1.1. Nutritional anamnesis*

The association of one or a few nutrients with a given disease has conceptual and methodo‐ logical limitations (Hu, 2002). These limitations are evidenced by the fact that they do not take into account the complex synergy between dietary nutrients, the cumulative effects and multiple nutrients that compose dietary patterns, the statistical significance that a wide range of chemical elements or foods can produce, and the relationship of association between the intake of certain nutrients and dietary patterns (Moeller et al., 2007). Hence, dietary pattern analysis has emerged as an alternative and complementary approach in nutritional epidemio‐ logical studies that evidence the relationship between the overall diet and the risk of chronic

Multivariate statistical analyses have been used for defining dietary patterns. Factor analysis, which includes both principal component analysis (PCA) and factorial analysis, is a multi‐ variate statistical technique that uses food intake data to identify common subjacent dietary factors or patterns (Hu, 2002; Moeller et al., 2007). Cluster analysis, another multivariate method, aggregates individuals into relatively homogeneous subgroups with similar dietary characteristics. These techniques allow the classification of individuals into distinct groups or in groups according to food intake frequency; classification of foods or food groups according to their percentage energy contribution or mean amount consumed in grams; establishment of nutrient intake patterns; and combination of dietary and biochemical measurements (Hu,

The association between dietary pattern and the prevalence of obesity and/or cardiovascular diseases has indicated a positive correlation between certain dietary patterns and indicators of these diseases (Berg et al., 2009; Howarth et al., 2007; Ma et al., 2003; Meyer et al., 2011; Newby et al., 2003; Neumann et al., 2007; Sherafat-kazemzadeh et al., 2010; Sichieri, 2002). Nevertheless, reviews on dietary patterns and their relationship with certain diseases have found data inconsistencies, signaling the need of more thorough studies on this theme

Based on the high frequency of food intake underreporting among the obese, some food groups and/or nutrients in the dietary patterns of obese women classified as energy intake underre‐ porters may vary, so more studies are needed to identify the intake particularities of this population. In our group, Ravelli (2013) found that women often underreported their energy intake and that underreporting was associated with a healthier dietary pattern than the pattern of women who reported their intake correctly. This suggests that underreporting involves

The objective of bariatric surgery is to reduce energy intake and consequently promote weight loss, better quality of life, and the improvement of associated comorbidities. Long-term weight loss maintenance depends on the development of a multidisciplinary education program focusing on the surgery, making patients and family members aware of its risks and benefits,

diseases (Hu, 2002).

40 Essentials and Controversies in Bariatric Surgery

2002; Moeller et al., 2007).

(Bhupathiraju; Tucker, 2011; Kant, 2004; Togo et al., 2001).

foods that obese individuals should restrict.

**5. Dietary approach of preoperative patients**

Nutritional anamnesis has a critical role in nutrition and health research. Its objective is to characterize the general nutritional status of an individual to determine the appropriate intervention.

Anamnesis consists of:

**•** Alcohol intake: the patients are asked about their drinking habits, including amount and frequency;

**•** The importance of the patient assuming a compromise with his/her health, since postoper‐ ative eating discipline is critical to avoid nutritional inadequacies and/or weight regain; **•** The intake of energy-dense fluids and alcoholic beverages and early or excessive inclusion

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

43

**•** Mastication – the patient must eat slowly to avoid the sensation of having food stuck on the way down, malaise, or even vomiting. This is valid for fluid and solid preparations;

**•** Advice and required dietary changes for the preoperative (fluid) and postoperative (fluid,

The advice regarding patients' new eating behavior should be provided by a dietician together with a psychologist to encourage patients to identify inappropriate eating behaviors and teach them new eating habits even before surgery. These recommendations increase postoperative adherence to the nutritional therapy and reduce the incidence of postoperative complications.

Nutritional counseling after surgery is essential because of all the changes patients must make to their eating habits. Follow-ups must be periodical to assess weight loss, encourage the adoption of healthy eating habits, clarify doubts, and identify possible nutritional inadequa‐

Nutritional recommendations may vary by type of surgery, but all of them have similar diet therapy objectives: to reduce the work of the stomach and intestinal overload in the immediate postoperative period and to promote healthy food choices and habits using a diet plan associated with specific, personalized nutritional supplementation to meet the nutritional

Patient noncompliance with postoperative control programs is usually high, especially one year after surgery, which means lower adherence to the recommended healthy behaviors, and consequently, risk of bariatric surgery failure. Therefore, it is essential for the patient to learn

Ingestion is forbidden in the 24 hours that follow surgery, regardless of type. After this period the patient may start ingesting fluids. The objective of the fluid diet is to allow gastric rest and adaptation to small volumes, promote systemic hydration, ease the digestive process and

Our patients are placed on a fluid diet three days before surgery and recommended to stay on the diet until the twentieth day after surgery. This diet must consist exclusively of fluids. Patients receive verbal advice and a written document containing instructions regarding

and recognize the importance of adherence to treatment before the surgery.

gastric emptying, and prevent the ingestion of residues (Aills et al., 2008).

cies. Counseling is critical to ensure surgery success and avoid future complications.

of simple sugars and fats may cause treatment failure or dumping syndrome;

soft, and general) periods, and foods that should be avoided after the surgery.

**•** Dumping syndrome – definition, symptoms, how to avoid;

**6. Dietary approach of postoperative patients**

requirements of the patient.

**6.1. Dietary changes**

We also take into account the reality of the patients, their jobs, routines, schedules, financial resources, literacy levels, and regional habits to personalize the intervention, otherwise it would be difficult to obtain good adherence to treatment.

The patients receive nutrition education based on the information collected by the nutritional anamneses, with emphasis on healthy food choices, the importance of consuming foods from all food groups, and the relationship between hunger and satiety. A personalized eating plan with lower energy content is created for the patients for them to start losing weight before surgery, reducing surgery risks and allowing us to assess their discipline.

The number and frequency of visits may vary according to the particularities of the patient and determination of the bariatric surgery team. The objective of the follow-ups is to assess adherence to the recommendations, weight loss, and changes in dietary habits, and to clarify surgery-related doubts. In the last visit prior to surgery, the patient and his/her companion receive verbal and written advice about the pre-and postoperative fluid diet.

Many issues are discussed with the patients in more detail during the visits, such as their need to lose 5% to 10% of their body weight before surgery, the preoperative eating plan, mastica‐ tion, surgical techniques and resulting nutritional changes, healthy food choices, and specifics about the fluid diet that should be followed before and after surgery, always emphasizing healthy food choices and habits. The nutritional intervention also has the following cognitive objectives:

**•** The surgery helps the patient to limit food intake by reducing gastric volume and absorption area, depending on surgical technique, thereby promoting weight loss;

The advice regarding patients' new eating behavior should be provided by a dietician together with a psychologist to encourage patients to identify inappropriate eating behaviors and teach them new eating habits even before surgery. These recommendations increase postoperative adherence to the nutritional therapy and reduce the incidence of postoperative complications.

## **6. Dietary approach of postoperative patients**

Nutritional counseling after surgery is essential because of all the changes patients must make to their eating habits. Follow-ups must be periodical to assess weight loss, encourage the adoption of healthy eating habits, clarify doubts, and identify possible nutritional inadequa‐ cies. Counseling is critical to ensure surgery success and avoid future complications.

Nutritional recommendations may vary by type of surgery, but all of them have similar diet therapy objectives: to reduce the work of the stomach and intestinal overload in the immediate postoperative period and to promote healthy food choices and habits using a diet plan associated with specific, personalized nutritional supplementation to meet the nutritional requirements of the patient.

Patient noncompliance with postoperative control programs is usually high, especially one year after surgery, which means lower adherence to the recommended healthy behaviors, and consequently, risk of bariatric surgery failure. Therefore, it is essential for the patient to learn and recognize the importance of adherence to treatment before the surgery.

#### **6.1. Dietary changes**

**•** Alcohol intake: the patients are asked about their drinking habits, including amount and

**•** Food-related emotional aspect: the patients are asked about how their emotions affect their

**•** Physical activity: the patients are asked about their physical endurance, the types of activity they performed in the past, and what they expect to achieve physically after surgery. At this time the patients are informed about the importance of starting a physical activity program

**•** Dietary history: collects information on snacking habits, mastication, fluid intake during

**•** Food preferences: investigates patients' food and preparation preferences, aversions, and

**•** Food intake: the patients are asked about their habitual food intake during weekdays and weekend days; intake frequency of the main foods of each food group; meal number and location; food preferences and aversions; possible religious and/or cultural food restrictions; and food preparation techniques and purchasing habits to identify preparation problems or facilities. We also routinely ask the patients to make a food diary on three nonconsecutive

We also take into account the reality of the patients, their jobs, routines, schedules, financial resources, literacy levels, and regional habits to personalize the intervention, otherwise it

The patients receive nutrition education based on the information collected by the nutritional anamneses, with emphasis on healthy food choices, the importance of consuming foods from all food groups, and the relationship between hunger and satiety. A personalized eating plan with lower energy content is created for the patients for them to start losing weight before

The number and frequency of visits may vary according to the particularities of the patient and determination of the bariatric surgery team. The objective of the follow-ups is to assess adherence to the recommendations, weight loss, and changes in dietary habits, and to clarify surgery-related doubts. In the last visit prior to surgery, the patient and his/her companion

Many issues are discussed with the patients in more detail during the visits, such as their need to lose 5% to 10% of their body weight before surgery, the preoperative eating plan, mastica‐ tion, surgical techniques and resulting nutritional changes, healthy food choices, and specifics about the fluid diet that should be followed before and after surgery, always emphasizing healthy food choices and habits. The nutritional intervention also has the following cognitive

**•** The surgery helps the patient to limit food intake by reducing gastric volume and absorption

supervised by a certified professional as soon as the surgeon releases them;

days, including a weekend day, to better determine their food intake profiles.

surgery, reducing surgery risks and allowing us to assess their discipline.

receive verbal and written advice about the pre-and postoperative fluid diet.

area, depending on surgical technique, thereby promoting weight loss;

would be difficult to obtain good adherence to treatment.

frequency;

eating habits;

intolerances;

objectives:

meals, and daily water intake;

42 Essentials and Controversies in Bariatric Surgery

Ingestion is forbidden in the 24 hours that follow surgery, regardless of type. After this period the patient may start ingesting fluids. The objective of the fluid diet is to allow gastric rest and adaptation to small volumes, promote systemic hydration, ease the digestive process and gastric emptying, and prevent the ingestion of residues (Aills et al., 2008).

Our patients are placed on a fluid diet three days before surgery and recommended to stay on the diet until the twentieth day after surgery. This diet must consist exclusively of fluids. Patients receive verbal advice and a written document containing instructions regarding volume, fractioning, the foods they may and may not consume, a menu example, recipes, and supplementation. The preoperative fluid diet differs from the postoperative fluid diet only in volume. During the hospitalization period, which varies from two to four days, the patients are given a residue-free fluid diet consisting only of water, light-colored tea, sugar-free gelatin dessert, isotonic drinks, coconut water, and stock.

complications include nutritional deficiencies, anemia, dumping syndrome, vomiting, and

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

45

Nutritional deficiencies (iron and anemia, calcium, vitamins D, B12, B6, and B1, zinc, and proteinenergy malnutrition) and their consequences may occur after surgery, especially in the longterm. The severity of these complications depends on the extension of the anatomic and physiological changes made to the gastrointestinal tract, as mentioned earlier. Nutritional deficiencies may cause severe morbidity and irreversible damage, and conventional supple‐ mentation is often not enough. Specific inadequacies must be corrected to restore normal serum levels and avoid greater consequences. It is essential to perform periodical tests as recommended by the guidelines to measure the serum levels of certain nutrients (Heber et al.,

Patients who undergo mixed surgeries (RYGB) and mostly malabsorptive mixed surgeries (BPD) require specific monitoring and supplementation, especially in the first year after surgery. Additional supplements of iron and calcium, water-soluble vitamins, and vitamins A and D are prescribed more often to BPD-DS (55%) patients than to RYGB (26%) patients

Bariatric patients require a minimum daily mineral and vitamin supplementation of one (AGB) to two (RYGB, BPD, and SG) multivitamin and multimineral tablets, 1200-1500 mg of elemental calcium in the form of citrate divided throughout the day, 3000 IU of vitamin D (to keep serum 25(OH)D above 30ng/mL), and enough vitamin B12 to maintain normal serum values. Vitamin B12 can be taken orally, sublingually, intranasally, or intramuscularly as follows: 350 mcg orally per day; or 500 mcg intranasally per week; or 1000 mcg intramuscularly per month; or 3000 mcg intramuscularly semiannually. Finally, the amount of folic acid present in multivitamins

The vitamin B12 status of all patients undergoing bariatric surgery, regardless of type, should be assessed before surgery, and of patients who lost the lower part of their stomach (SG, RYGB and BPD), should also be assessed annually after surgery. Supplementation with 1000 ug or more of crystalline vitamin B12 daily may be necessary to maintain adequate serum levels of

Conventional or additional supplementation should provide 45 to 60 mg of iron per day. Iron serum levels should be monitored in all bariatric surgery patients and individuals with irondeficiency anemia. Anemia treatment includes the prescription of 150 to 200 mg of elemental iron orally per day in the form of iron sulfate, fumarate, or gluconate. Vitamin C may be taken simultaneously to increase iron absorption. Intravenous iron infusion is indicated for patients with severe deficiency, oral intolerance, or refractory anemia due to severe iron malabsorption. Nutritional anemia stemming from malabsorptive bariatric surgeries also include deficiency of vitamin B12, folic acid, protein-energy, copper, selenium, and zinc, so these deficiencies must

Protein-energy malnutrition is usually accompanied by hypoalbuminemia, alopecia, asthenia, and anemia. Some studies have found that two years after surgery, 5% to 13% of RYGB patients and 3% to 18% of BPD patients have hypoalbuminemia. Bariatric patients should ingest at least

be assessed and corrected in patients with persistent anemia (Aills et al., 2008).

is adequate (400 mcg) (Mechanick et al., 2009; Mechanick, et al., 2013).

alopecia.

2010).

(Aasheim et al., 2009).

this vitamin (Kehagias et al., 2011).

All diets are adapted to the type of surgery and the particularities of each patient. When our patients return for a follow-up visit fifteen days after the surgery, we verify the volume they are ingesting, meal fractioning, the use of protein and micronutrient supplements, daily water intake, voiding habits, bowel movements, possible eating difficulties, and physical signs of nutritional deficiencies. Our patients also receive verbal and written advice about the soft diet that should be started twenty days after the surgery.

The second follow-up visit occurs 25 to 35 days after surgery. During this visit, we advise patients about the general diet, examine them for physical signs of nutritional deficiencies, and collect information about food intake during the soft-diet period, such as amounts consumed, number of meals consumed per day, ingestion of the recommended nutrient supplements, water intake, voiding habits, bowel movements, and eating difficulties. We also advise the patients to start the general diet slowly, according to their recovery and food acceptance. The general diet (solid) should begin 35 days after surgery.

Bariatric surgery patients should be nutritionally monitored. Visiting the dietician regularly is extremely important because the small volume of the stomach greatly restricts nutrient intake. In the first months after surgery, nausea and vomiting are common; nevertheless, they must be investigated and the patients, counseled (Mechanick et al. 2009). The follow-up schedule may vary according to individual needs and possible surgery complications. Some patients even require special follow-up (Mechanick et al., 2009). We ask our patients to visit us once a month for five months after they start the general diet, then quarterly for six months, then semiannually or as needed.

Nutritional care after bariatric surgery has two objectives: the first is to adjust the energy and nutrient intakes necessary for tissue repair after surgery and for preserving lean body mass during extreme weight loss, and the second is to minimize the symptoms caused by surgeryinduced changes, such as reflux, early satiety, and dumping syndrome (Aills et al., 2008).

The manner in which postoperative weight loss factors interact determines how surgery affects body weight in the short and long terms, hence the importance of knowing the weight loss pattern and related factors. Long-term follow-up is also advised to monitor the outcome and make sure that the surgery-related benefits are long-lived.

## **7. Dietary approaches to prevent and treat postoperative complications**

The main comorbidities associated with obesity, such as diabetes and high blood pressure, improve significantly shortly after bariatric surgery, but other complications may arise given the surgery-induced anatomic and physiological changes. The most common postoperative complications include nutritional deficiencies, anemia, dumping syndrome, vomiting, and alopecia.

volume, fractioning, the foods they may and may not consume, a menu example, recipes, and supplementation. The preoperative fluid diet differs from the postoperative fluid diet only in volume. During the hospitalization period, which varies from two to four days, the patients are given a residue-free fluid diet consisting only of water, light-colored tea, sugar-free gelatin

All diets are adapted to the type of surgery and the particularities of each patient. When our patients return for a follow-up visit fifteen days after the surgery, we verify the volume they are ingesting, meal fractioning, the use of protein and micronutrient supplements, daily water intake, voiding habits, bowel movements, possible eating difficulties, and physical signs of nutritional deficiencies. Our patients also receive verbal and written advice about the soft diet

The second follow-up visit occurs 25 to 35 days after surgery. During this visit, we advise patients about the general diet, examine them for physical signs of nutritional deficiencies, and collect information about food intake during the soft-diet period, such as amounts consumed, number of meals consumed per day, ingestion of the recommended nutrient supplements, water intake, voiding habits, bowel movements, and eating difficulties. We also advise the patients to start the general diet slowly, according to their recovery and food acceptance. The

Bariatric surgery patients should be nutritionally monitored. Visiting the dietician regularly is extremely important because the small volume of the stomach greatly restricts nutrient intake. In the first months after surgery, nausea and vomiting are common; nevertheless, they must be investigated and the patients, counseled (Mechanick et al. 2009). The follow-up schedule may vary according to individual needs and possible surgery complications. Some patients even require special follow-up (Mechanick et al., 2009). We ask our patients to visit us once a month for five months after they start the general diet, then quarterly for six months,

Nutritional care after bariatric surgery has two objectives: the first is to adjust the energy and nutrient intakes necessary for tissue repair after surgery and for preserving lean body mass during extreme weight loss, and the second is to minimize the symptoms caused by surgeryinduced changes, such as reflux, early satiety, and dumping syndrome (Aills et al., 2008).

The manner in which postoperative weight loss factors interact determines how surgery affects body weight in the short and long terms, hence the importance of knowing the weight loss pattern and related factors. Long-term follow-up is also advised to monitor the outcome and

**7. Dietary approaches to prevent and treat postoperative complications**

The main comorbidities associated with obesity, such as diabetes and high blood pressure, improve significantly shortly after bariatric surgery, but other complications may arise given the surgery-induced anatomic and physiological changes. The most common postoperative

dessert, isotonic drinks, coconut water, and stock.

44 Essentials and Controversies in Bariatric Surgery

that should be started twenty days after the surgery.

general diet (solid) should begin 35 days after surgery.

make sure that the surgery-related benefits are long-lived.

then semiannually or as needed.

Nutritional deficiencies (iron and anemia, calcium, vitamins D, B12, B6, and B1, zinc, and proteinenergy malnutrition) and their consequences may occur after surgery, especially in the longterm. The severity of these complications depends on the extension of the anatomic and physiological changes made to the gastrointestinal tract, as mentioned earlier. Nutritional deficiencies may cause severe morbidity and irreversible damage, and conventional supple‐ mentation is often not enough. Specific inadequacies must be corrected to restore normal serum levels and avoid greater consequences. It is essential to perform periodical tests as recommended by the guidelines to measure the serum levels of certain nutrients (Heber et al., 2010).

Patients who undergo mixed surgeries (RYGB) and mostly malabsorptive mixed surgeries (BPD) require specific monitoring and supplementation, especially in the first year after surgery. Additional supplements of iron and calcium, water-soluble vitamins, and vitamins A and D are prescribed more often to BPD-DS (55%) patients than to RYGB (26%) patients (Aasheim et al., 2009).

Bariatric patients require a minimum daily mineral and vitamin supplementation of one (AGB) to two (RYGB, BPD, and SG) multivitamin and multimineral tablets, 1200-1500 mg of elemental calcium in the form of citrate divided throughout the day, 3000 IU of vitamin D (to keep serum 25(OH)D above 30ng/mL), and enough vitamin B12 to maintain normal serum values. Vitamin B12 can be taken orally, sublingually, intranasally, or intramuscularly as follows: 350 mcg orally per day; or 500 mcg intranasally per week; or 1000 mcg intramuscularly per month; or 3000 mcg intramuscularly semiannually. Finally, the amount of folic acid present in multivitamins is adequate (400 mcg) (Mechanick et al., 2009; Mechanick, et al., 2013).

The vitamin B12 status of all patients undergoing bariatric surgery, regardless of type, should be assessed before surgery, and of patients who lost the lower part of their stomach (SG, RYGB and BPD), should also be assessed annually after surgery. Supplementation with 1000 ug or more of crystalline vitamin B12 daily may be necessary to maintain adequate serum levels of this vitamin (Kehagias et al., 2011).

Conventional or additional supplementation should provide 45 to 60 mg of iron per day. Iron serum levels should be monitored in all bariatric surgery patients and individuals with irondeficiency anemia. Anemia treatment includes the prescription of 150 to 200 mg of elemental iron orally per day in the form of iron sulfate, fumarate, or gluconate. Vitamin C may be taken simultaneously to increase iron absorption. Intravenous iron infusion is indicated for patients with severe deficiency, oral intolerance, or refractory anemia due to severe iron malabsorption. Nutritional anemia stemming from malabsorptive bariatric surgeries also include deficiency of vitamin B12, folic acid, protein-energy, copper, selenium, and zinc, so these deficiencies must be assessed and corrected in patients with persistent anemia (Aills et al., 2008).

Protein-energy malnutrition is usually accompanied by hypoalbuminemia, alopecia, asthenia, and anemia. Some studies have found that two years after surgery, 5% to 13% of RYGB patients and 3% to 18% of BPD patients have hypoalbuminemia. Bariatric patients should ingest at least 60 grams of protein a day, or 1.5g/kg of the ideal body weight a day, or if necessary 2.1g/kg of the ideal body weight a day (Mechanick, et al., 2013).

feeling nauseated, vomiting, or feeling that the bolus got stuck somewhere between the throat

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

47

Patients with persistent vomiting who chew well but are intolerant to solids should be specifically examined for stenosis by the surgeon to rule out functional disorders, even if the

Frequent vomiting may cause thiamine deficiency. Thiamine should be part of the conven‐ tional supplementation, as the other water-soluble vitamins. Susceptible patients include those with rapid weight loss, prolonged vomiting, excessive alcohol intake, neuropathy, encephal‐ opathy, and heart failure. Patients with suspected or established severe thiamine deficiency should receive 500mg of intravenous thiamine daily for three to five days, followed by 250 mg daily for three to five days until the symptoms subside. Health care providers should consider further supplementation with 100mg orally per day for an indeterminate period or until the

Dumping syndrome is a common bariatric surgery complication experienced by roughly 70% of RYGB patients. Foods with high osmolarity, such as those with high sugar content, cause osmotic overload in the small intestine (Fujioka, 2005; Mechanick et al., 2009). The symptoms include hypoglycemia, abdominal pain, nausea, diarrhea, rubor, and tachycardia (Elliot, 2003; Merchanick et al., 2009). Late dumping syndrome symptoms may be caused by reactive hypoglycemia, normally controlled through diet or treated prophylactically with half a cup of

Bariatric patients must learn about dumping syndrome, its symptoms, and which foods to avoid before surgery. During the nutrition education process, we strongly encourage our patients to restrict the intake of simple sugars and reduce the intake of high-fat foods before and after surgery. Patients are also encouraged to eat small amounts at a time, avoid ingesting fluids thirty minutes before and after a solid meal, prefer complex carbohydrates to simple

Alopecia, classified as a nutritional complication of bariatric surgery, occurs mainly in the first year after surgery, a time of intense weight loss and patients' adaptation to diet and their new gastrointestinal system. Nutritional deficiency-related alopecia is mainly associated with the deficiency of zinc, iron, proteins, and essential fatty acids, so requires proper supplementation.

Most bariatric patients may experience one or more nutritional deficiencies, justifying the need of lifelong vitamin and mineral supplementation after surgery, and macronutrient supple‐ mentation when necessary. Thus, the dietician assumes the critical role of preventing and

Bariatric surgery promotes the control of obesity, not the cure, and complications may occur at any time (Novais et al., 2010). Weight loss after bariatric surgery is clearly visible, with

intolerance developed postoperatively (Fujioka, 2005).

risk factors are eliminated (Mechanick, et al., 2009).

correcting nutritional changes after bariatric surgery.

**8. Dietary approach for preventing weight regain**

ones, and increase protein intake.

orange juice roughly one hour after a meal (Mechanick et al., 2009).

and the stomach.

Bone loss may occur in the long run, especially in women, so complete assessment of calcium metabolism is essential to make sure that the ingested and absorbed amounts are enough to prevent metabolic bone disease. RYGB, BPD, or BPD-DS patients must take calcium citrate and vitamin D [ergocalciferol (D2) or cholecalciferol (D3)] orally to prevent or minimize secondary hyperparathyroidism without inducing hypercalciuria. In severe cases of vitamin D malab‐ sorption, oral doses may be increased to 50,000 IU one to three times a week or even daily. Hypophosphatemia is usually due to vitamin D deficiency. An oral phosphate supplement should be taken when the serum level is in the 1.5 to 2.5 mg/dL bracket (Mechanick, et al., 2013).

Vitamin A deficiency may cause vision problems. Supplementation, isolated or combined with other fat-soluble vitamins, is recommended for patients who undergo purely malabsorptive procedures, such as BPD or BPD-DS. There is no evidence to suggest that bariatric surgery patients should be routinely screened for low levels of essential fatty acids, vitamin E, or vitamin K. However, health care providers should consider vitamin K assessment when they find an established deficiency of fat-soluble vitamins (hepatopathy, coagulopathy, or osteo‐ porosis) (Aasheim et al., 2009).

There is also no evidence to suggest that routine selenium screening or supplementation is necessary after bariatric surgery. Nevertheless, health care providers should measure the serum selenium levels of patients who undergo malabsorptive surgeries or of patients with anemia, fatigue, persistent diarrhea, cardiomyopathy, or metabolic bone disease. Zinc deficiency should be assessed routinely in BPD or BPD-DS patients or patients with alopecia, ageusia, and dysgeusia (Aills et al., 2008).

Copper supplementation (2 mg/day) should be included as part of the supplementation routine. Consider measuring the serum copper level of patients with persistent anemia, neutropenia, myeloneuropathy, and poor wound healing. Patients being treated for zinc deficiency and alopecia should take 1 mg of copper for each 8 to 15 mg of zinc since zinc supplementation may cause copper deficiency (Mechanick, et al., 2013).

Vomiting may occur in the postoperative period, especially in the first months after surgery, and is generally precipitated by eating more than the stomach can hold or not chewing well. It may also indicate other problems, such as stenosis or intolerance to solid foods (Fujioka, 2005).

Intolerance to solid foods is the main characteristic of patients who are not chewing foods well enough, especially foods that are harder to chew, such as meats, non-starchy vegetables, and all foods with a more fibrous consistency. These patients prefer softer foods, such as soups (with a high proportion of carbohydrates), pasta, puree, soufflé, ice cream, cookies, certain savory snacks and pastries, and other foods that do not require much effort to chew and swallow.

After surgery bariatric patients may also experience trauma or fear for not knowing how much food to put in their mouths at a time or how much to chew before swallowing, and end up feeling nauseated, vomiting, or feeling that the bolus got stuck somewhere between the throat and the stomach.

60 grams of protein a day, or 1.5g/kg of the ideal body weight a day, or if necessary 2.1g/kg of

Bone loss may occur in the long run, especially in women, so complete assessment of calcium metabolism is essential to make sure that the ingested and absorbed amounts are enough to prevent metabolic bone disease. RYGB, BPD, or BPD-DS patients must take calcium citrate and vitamin D [ergocalciferol (D2) or cholecalciferol (D3)] orally to prevent or minimize secondary hyperparathyroidism without inducing hypercalciuria. In severe cases of vitamin D malab‐ sorption, oral doses may be increased to 50,000 IU one to three times a week or even daily. Hypophosphatemia is usually due to vitamin D deficiency. An oral phosphate supplement should be taken when the serum level is in the 1.5 to 2.5 mg/dL bracket (Mechanick, et al., 2013).

Vitamin A deficiency may cause vision problems. Supplementation, isolated or combined with other fat-soluble vitamins, is recommended for patients who undergo purely malabsorptive procedures, such as BPD or BPD-DS. There is no evidence to suggest that bariatric surgery patients should be routinely screened for low levels of essential fatty acids, vitamin E, or vitamin K. However, health care providers should consider vitamin K assessment when they find an established deficiency of fat-soluble vitamins (hepatopathy, coagulopathy, or osteo‐

There is also no evidence to suggest that routine selenium screening or supplementation is necessary after bariatric surgery. Nevertheless, health care providers should measure the serum selenium levels of patients who undergo malabsorptive surgeries or of patients with anemia, fatigue, persistent diarrhea, cardiomyopathy, or metabolic bone disease. Zinc deficiency should be assessed routinely in BPD or BPD-DS patients or patients with alopecia,

Copper supplementation (2 mg/day) should be included as part of the supplementation routine. Consider measuring the serum copper level of patients with persistent anemia, neutropenia, myeloneuropathy, and poor wound healing. Patients being treated for zinc deficiency and alopecia should take 1 mg of copper for each 8 to 15 mg of zinc since zinc

Vomiting may occur in the postoperative period, especially in the first months after surgery, and is generally precipitated by eating more than the stomach can hold or not chewing well. It may also indicate other problems, such as stenosis or intolerance to solid foods (Fujioka,

Intolerance to solid foods is the main characteristic of patients who are not chewing foods well enough, especially foods that are harder to chew, such as meats, non-starchy vegetables, and all foods with a more fibrous consistency. These patients prefer softer foods, such as soups (with a high proportion of carbohydrates), pasta, puree, soufflé, ice cream, cookies, certain savory snacks and pastries, and other foods that do not require much effort to chew and

After surgery bariatric patients may also experience trauma or fear for not knowing how much food to put in their mouths at a time or how much to chew before swallowing, and end up

supplementation may cause copper deficiency (Mechanick, et al., 2013).

the ideal body weight a day (Mechanick, et al., 2013).

46 Essentials and Controversies in Bariatric Surgery

porosis) (Aasheim et al., 2009).

2005).

swallow.

ageusia, and dysgeusia (Aills et al., 2008).

Patients with persistent vomiting who chew well but are intolerant to solids should be specifically examined for stenosis by the surgeon to rule out functional disorders, even if the intolerance developed postoperatively (Fujioka, 2005).

Frequent vomiting may cause thiamine deficiency. Thiamine should be part of the conven‐ tional supplementation, as the other water-soluble vitamins. Susceptible patients include those with rapid weight loss, prolonged vomiting, excessive alcohol intake, neuropathy, encephal‐ opathy, and heart failure. Patients with suspected or established severe thiamine deficiency should receive 500mg of intravenous thiamine daily for three to five days, followed by 250 mg daily for three to five days until the symptoms subside. Health care providers should consider further supplementation with 100mg orally per day for an indeterminate period or until the risk factors are eliminated (Mechanick, et al., 2009).

Dumping syndrome is a common bariatric surgery complication experienced by roughly 70% of RYGB patients. Foods with high osmolarity, such as those with high sugar content, cause osmotic overload in the small intestine (Fujioka, 2005; Mechanick et al., 2009). The symptoms include hypoglycemia, abdominal pain, nausea, diarrhea, rubor, and tachycardia (Elliot, 2003; Merchanick et al., 2009). Late dumping syndrome symptoms may be caused by reactive hypoglycemia, normally controlled through diet or treated prophylactically with half a cup of orange juice roughly one hour after a meal (Mechanick et al., 2009).

Bariatric patients must learn about dumping syndrome, its symptoms, and which foods to avoid before surgery. During the nutrition education process, we strongly encourage our patients to restrict the intake of simple sugars and reduce the intake of high-fat foods before and after surgery. Patients are also encouraged to eat small amounts at a time, avoid ingesting fluids thirty minutes before and after a solid meal, prefer complex carbohydrates to simple ones, and increase protein intake.

Alopecia, classified as a nutritional complication of bariatric surgery, occurs mainly in the first year after surgery, a time of intense weight loss and patients' adaptation to diet and their new gastrointestinal system. Nutritional deficiency-related alopecia is mainly associated with the deficiency of zinc, iron, proteins, and essential fatty acids, so requires proper supplementation.

Most bariatric patients may experience one or more nutritional deficiencies, justifying the need of lifelong vitamin and mineral supplementation after surgery, and macronutrient supple‐ mentation when necessary. Thus, the dietician assumes the critical role of preventing and correcting nutritional changes after bariatric surgery.

## **8. Dietary approach for preventing weight regain**

Bariatric surgery promotes the control of obesity, not the cure, and complications may occur at any time (Novais et al., 2010). Weight loss after bariatric surgery is clearly visible, with consequent improvement of the comorbidities and quality of life. Therefore, weight loss is considered one of the main parameters for defining bariatric surgery success (Brolin, 2002; Brolin, 2007; Silver et al., 2006; Novais et al., 2010). Researchers unanimously agree that a successful outcome requires an excess weight loss (%EWL) of at least 50% and the long-term maintenance of the weight loss (Capella, Capella, 1996; Brolin et al., 1994; Brolin, 2002; Fobi, 2004; Brolin 2007; Silver et al., 2006; Novais, 2010).

The relationship between psychologist and dietician is essential to treat each patient individ‐ ually. Many patients do not assimilate so many changes, justifying their weight regain or replacement of a symptom by another eating disorder or compulsive behavior.  The importance of psychological and sometimes psychiatric followup is clear as it helps to improve patients' quality of life and interpersonal relationships.

Theoretical Bases and Dietary Approach of Bariatric Patients

http://dx.doi.org/10.5772/58636

49

Weight regain after bariatric surgery is a reality, hence the need of prospective studies with patients in line for bariatric surgery and the critical work of a multidisciplinary team to provide the best treatment possible and ensure a successful outcome, not only in terms of weight loss

As a result of the knowledge we have accumulated in our clinical and research practice and consonant with the literature, we can state that bariatric surgery changes the nourishment process substantially, implying the need of permanently monitoring the patients' nutritional status. This practice should begin already in the waiting line for bariatric surgery because nutritional deficiencies may occur in obese individuals despite their excessive food intake; they

In addition to anthropometric assessment, patients should undergo a thorough assessment of the signs and symptoms associated with nutritional deficiencies, measurement of serum nutrient levels, and food intake assessment. Food intake assessment has technical and operational limitations, but it is an essential tool for dietary diagnosis and prescription, and for food and nutrition education. Food and nutrition education must be based on science and supported by the other professionals in the team. In addition to a dietician, a psychologist is needed to help patients to develop the skills they need to practice self-care. Furthermore, although surgery improves the metabolic disorders associated with adipose tissue, nutritional deficiencies should always be a target of concern, prophylactic intervention, and monitoring. Therefore, a multidisciplinary health care team is critically needed for providing the lifelong

Patrícia Fátima Sousa Novais1,2,3, Flávia Andreia Marin1,2,3, Alex Harley Crisp1,2,3,

3 Clinica Bariátrica – Hospital dos Fornecedores de Cana, Piracicaba SP, Brazil

and Maria Rita Marques de Oliveira1,2,3

but also in terms of body nourishment and quality of life.

**9. Final considerations**

may either have a poor diet.

care required by bariatric patients.

Irineu Rasera Junior1,2,3, Celso Vieira de Souza Leite1

1 Universidade Estadual Paulista, Botucatu SP, Brazil

2 Universidade Estadual Paulista, Araraquara SP, Brazil

**Author details**

Weight regain after surgery may be promoted by physiological adaptations of the gastroin‐ testinal tract. Adoption of a healthy lifestyle protects bariatric patients from old habits directly related to obesity. This new behavior is important to maintain the new body weight in the long run, so the support of a certified multidisciplinary team is critical (Bond et al., 2004; Novais et al., 2010).

Weight loss and control after surgery are checked routinely. Many indicators are used for this purpose, such as BMI, percentage of the initial weight loss, and percentage of excess weight loss. We use the latter in our practice.

Most of the weight loss occurs in the six months after surgery, when food intake restriction is greater (Novais et al., 2010). Patients submitted to malabsorptive procedures may lose 0.2 – 0.5 kg per day, achieving a loss of 18 – 40.5 kg in the first three months after surgery. The weight lost peaks between 12 and 18 months after surgery (Mechanick et al., 2009, Novais et al., 2010).

Small weight loss after surgery should be investigated by the multidisciplinary team. The dietician must check the patient's food habits, especially the intake of energy-dense foods. Some studies found that even bariatric patients may regain weight (Kaplan, 2005; Livingston, 2005), especially three to five years after surgery (Brolin *et al.*, 1994; Buchwald et al., 2004; Mechanick et al., 2009). Obesity may recur because it is a chronic disease. Patients must understand that weight fluctuations are normal and perfectly acceptable. Weight-loss plateau or even a small weight regain are part of the normal weight loss process. Professionals must emphasize on the better quality of life, healthy behaviors, and better health status instead of percentage of excess weight loss as a measure of success.

Our group (Novais, 2009) investigated the food intake, weight history, and quality of life of 141 females two years after bariatric surgery and found that 84.4% lost more than 50% of their excess perioperative weight. Significant weight loss occurred in the first six months after surgery and stabilized two years after surgery. About 15% of the patients regained part of their excess weight. In another study our group (Fogaça, 2009) assessed the factors associated with weight regain in women two years after bariatric surgery and found that the resting energy expenditure adjusted for total and lean body mass, and the serum lipids, glucose, insulin, and leptin of women who regained more than 10% of their weight did not differ significantly from those of the controls-women who did not regain weight.

Food habits impact weight loss speed and long-term maintenance. Hence, dieticians and psychologists work side by side with bariatric patients with eating disorders that may promote weight regain. Psychologists help patients to find skills that satisfy their emotional needs and dieticians help them to effectively learn to nourish their minds and bodies, enabling them to deal with their emotions, desires, and biological needs.

The relationship between psychologist and dietician is essential to treat each patient individ‐ ually. Many patients do not assimilate so many changes, justifying their weight regain or replacement of a symptom by another eating disorder or compulsive behavior.  The importance of psychological and sometimes psychiatric followup is clear as it helps to improve patients' quality of life and interpersonal relationships.

Weight regain after bariatric surgery is a reality, hence the need of prospective studies with patients in line for bariatric surgery and the critical work of a multidisciplinary team to provide the best treatment possible and ensure a successful outcome, not only in terms of weight loss but also in terms of body nourishment and quality of life.

## **9. Final considerations**

consequent improvement of the comorbidities and quality of life. Therefore, weight loss is considered one of the main parameters for defining bariatric surgery success (Brolin, 2002; Brolin, 2007; Silver et al., 2006; Novais et al., 2010). Researchers unanimously agree that a successful outcome requires an excess weight loss (%EWL) of at least 50% and the long-term maintenance of the weight loss (Capella, Capella, 1996; Brolin et al., 1994; Brolin, 2002; Fobi,

Weight regain after surgery may be promoted by physiological adaptations of the gastroin‐ testinal tract. Adoption of a healthy lifestyle protects bariatric patients from old habits directly related to obesity. This new behavior is important to maintain the new body weight in the long run, so the support of a certified multidisciplinary team is critical (Bond et al., 2004; Novais et

Weight loss and control after surgery are checked routinely. Many indicators are used for this purpose, such as BMI, percentage of the initial weight loss, and percentage of excess weight

Most of the weight loss occurs in the six months after surgery, when food intake restriction is greater (Novais et al., 2010). Patients submitted to malabsorptive procedures may lose 0.2 – 0.5 kg per day, achieving a loss of 18 – 40.5 kg in the first three months after surgery. The weight lost peaks between 12 and 18 months after surgery (Mechanick et al., 2009, Novais et al., 2010). Small weight loss after surgery should be investigated by the multidisciplinary team. The dietician must check the patient's food habits, especially the intake of energy-dense foods. Some studies found that even bariatric patients may regain weight (Kaplan, 2005; Livingston, 2005), especially three to five years after surgery (Brolin *et al.*, 1994; Buchwald et al., 2004; Mechanick et al., 2009). Obesity may recur because it is a chronic disease. Patients must understand that weight fluctuations are normal and perfectly acceptable. Weight-loss plateau or even a small weight regain are part of the normal weight loss process. Professionals must emphasize on the better quality of life, healthy behaviors, and better health status instead of

Our group (Novais, 2009) investigated the food intake, weight history, and quality of life of 141 females two years after bariatric surgery and found that 84.4% lost more than 50% of their excess perioperative weight. Significant weight loss occurred in the first six months after surgery and stabilized two years after surgery. About 15% of the patients regained part of their excess weight. In another study our group (Fogaça, 2009) assessed the factors associated with weight regain in women two years after bariatric surgery and found that the resting energy expenditure adjusted for total and lean body mass, and the serum lipids, glucose, insulin, and leptin of women who regained more than 10% of their weight did not differ significantly from

Food habits impact weight loss speed and long-term maintenance. Hence, dieticians and psychologists work side by side with bariatric patients with eating disorders that may promote weight regain. Psychologists help patients to find skills that satisfy their emotional needs and dieticians help them to effectively learn to nourish their minds and bodies, enabling them to

2004; Brolin 2007; Silver et al., 2006; Novais, 2010).

percentage of excess weight loss as a measure of success.

those of the controls-women who did not regain weight.