Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids. Effects of energy-restricted diets containing increased protein on weight loss, resting energy expenditure, and the thermic effect of feeding in type 2 diabetes. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women Effect of a high-protein, energy-restricted diet on weight loss and energy expenditure after weight stabilization in hyperinsulinemic subjects Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo. Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. A High-Protein Diet With Resistance Exercise Training Improves Weight Loss and Body Composition in Overweight and Obese Patients With Type 2 Diabetes Effects of dietary composition on energy expenditure during weight-loss maintenance. High protein vs high carbohydrate hypoenergetic diet for the treatment of obese hyperinsulinemic subjects Effects of increased dietary protein-to-carbohydrate ratios in women with polycystic ovary syndrome. The satiating effect of dietary protein is unrelated to postprandial ghrelin secretion. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects Effects of a popular exercise and weight loss program on weight loss, body composition, energy expenditure and health in obese women High-protein, low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults. High protein intake sustains weight maintenance after body weight loss in humans Effect of Diet Composition on Energy Expenditure during Weight Loss: The POUNDS LOST Study Effects of protein vs. carbohydrate-rich diets on fuel utilisation in obese women during weight loss. Effects of a low-glycemic load diet on resting energy expenditure and heart disease risk factors during weight loss. Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women Effect of a high-protein, high-monounsaturated fat weight loss diet on glycemic control and lipid levels in type 2 diabetes. Long-term effects of a low carbohydrate, low fat or high unsaturated fat diet compared to a no-intervention control. Effects of an 8-week high-protein or high-carbohydrate diet in adults with hyperinsulinemia. The effect of protein intake on 24-h energy expenditure during energy restriction.
BACKGROUND When substituted for carbohydrate in an energy-reduced diet , dietary protein enhances fat loss in women . It is unknown whether the effect is due to increased protein or reduced carbohydrate . OBJECTIVE We compared the effects of 2 isocaloric diets that differed in protein and fat content on weight loss , lipids , appetite regulation , and energy expenditure after test meals . DESIGN This was a parallel , r and omized study in which subjects received either a low-fat , high-protein ( LF-HP ) diet ( 29 + /- 1 % fat , 34 + /- 0.8 % protein ) or a high-fat , st and ard-protein ( HF-SP ) diet ( 45 + /- 0.6 % fat , 18 + /- 0.3 % protein ) during 12 wk of energy restriction ( 6 + /- 0.1 MJ/d ) and 4 wk of energy balance ( 7.4 + /- 0.3 MJ/d ) . Fifty-seven overweight and obese [ mean body mass index ( in kg/m(2 ) ) : 33.8 + /- 0.9 ] volunteers with insulin concentrations > 12 mU/L completed the study . RESULTS Weight loss ( LF-HP group , 9.7 + /- 1.1 kg ; HF-SP group , 10.2 + /- 1.4 kg ; P = 0.78 ) and fat loss were not significantly different between diet groups even though the subjects desired less to eat after the LF-HP meal ( P = 0.02 ) . The decrease in resting energy expenditure was not significantly different between diet groups ( LF-HP , -342 + /- 185 kJ/d ; HF-SP , -349 + /- 220 kJ/d ) . The decrease in the thermic effect of feeding with weight loss was smaller in the LF-HP group than in the HF-SP group ( -0.3 + /- 1.0 % compared with -3.6 + /- 0.7 % ; P = 0.014 ) . Glucose and insulin responses to test meals improved after weight loss ( P < 0.001 ) with no significant diet effect . Bone turnover , inflammation , and calcium excretion did not change significantly . CONCLUSION The magnitude of weight loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets , and neither diet had any detrimental effects on bone turnover or renal function OBJECTIVE To determine the effect of a high-protein ( HP ) diet compared with a low-protein ( LP ) diet on weight loss , resting energy expenditure ( REE ) , and the thermic effect of food ( TEF ) in subjects with type 2 diabetes during moderate energy restriction . RESEARCH DESIGN AND METHODS In this study , 26 obese subjects with type 2 diabetes consumed a HP ( 28 % protein , 42 % carbohydrate ) or LP diet ( 16 % protein , 55 % carbohydrate ) during 8 weeks of energy restriction ( 1,600 kcal/day ) and 4 weeks of energy balance . Body weight and composition and REE were measured , and the TEF in response to a HP or LP meal was determined for 2 h , at weeks 0 and 12 . RESULTS The mean weight loss was 4.6 + /- 0.4 kg ( P < 0.001 ) , of which 4.5 + /- 0.4 kg was fat ( P < 0.001 ) , with no effect of diet ( P = 0.6 ) . At both weeks 0 and 12 , TEF was greater after the HP than after the LP meal ( 0.064 vs. 0.050 kcal x kcal(-1 ) energy consumed x 2 h(-1 ) , respectively ; overall diet effect , P = 0.003 ) . REE and TEF were reduced similarly with each of the diets ( time effects , P = 0.02 and P < 0.001 , respectively ) . CONCLUSIONS In patients with type 2 diabetes , a low-fat diet with an increased protein-to-carbohydrate ratio does not significantly increase weight loss or blunt the fall in REE BACKGROUND It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism . OBJECTIVE The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition , glucose and lipid metabolism , and markers of bone turnover . DESIGN A parallel design included either a high-protein diet of meat , poultry , and dairy foods ( HP diet : 27 % of energy as protein , 44 % as carbohydrate , and 29 % as fat ) or a st and ard-protein diet low in those foods ( SP diet : 16 % of energy as protein , 57 % as carbohydrate , and 27 % as fat ) during 12 wk of energy restriction ( 6 - 6.3 MJ/d ) and 4 wk of energy balance ( approximately 8.2 MJ/d ) . Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study . RESULTS Weight loss ( 7.9 + /- 0.5 kg ) and total fat loss ( 6.9 + /- 0.4 kg ) did not differ between diet groups . In women , total lean mass was significantly ( P = 0.02 ) better preserved with the HP diet ( -0.1 + /- 0.3 kg ) than with the SP diet ( -1.5 + /- 0.3 kg ) . Those fed the HP diet had significantly ( P < 0.03 ) less glycemic response at weeks 0 and 16 than did those fed the SP diet . After weight loss , the glycemic response decreased significantly ( P < 0.05 ) more in the HP diet group . The reduction in serum triacylglycerol concentrations was significantly ( P < 0.05 ) greater in the HP diet group ( 23 % ) than in the SP diet group ( 10 % ) . Markers of bone turnover , calcium excretion , and systolic blood pressure were unchanged . CONCLUSION Replacing carbohydrate with protein from meat , poultry , and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion Objective To compare the effects of isocaloric , energy-restricted very low-carbohydrate ketogenic ( VLCK ) and low-fat ( LF ) diets on weight loss , body composition , trunk fat mass , and resting energy expenditure ( REE ) in overweight/obese men and women . Design R and omized , balanced , two diet period clinical intervention study . Subjects were prescribed two energy-restricted ( -500 kcal/day ) diets : a VLCK diet with a goal to decrease carbohydrate levels below 10 % of energy and induce ketosis and a LF diet with a goal similar to national recommendations ( % carbohydrate : fat : protein = ~60:25:15%).Subjects15 healthy , overweight/obese men ( mean ± s.e.m . : age 33.2 ± 2.9 y , body mass 109.1 ± 4.6 kg , body mass index 34.1 ± 1.1 kg/m2 ) and 13 premenopausal women ( age 34.0 ± 2.4 y , body mass 76.3 ± 3.6 kg , body mass index 29.6 ± 1.1 kg/m2 ) . Measurements Weight loss , body composition , trunk fat ( by dual-energy X-ray absorptiometry ) , and resting energy expenditure ( REE ) were determined at baseline and after each diet intervention . Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person . Results Actual nutrient intakes from food records during the VLCK ( % carbohydrate : fat : protein = ~9:63:28 % ) and the LF ( ~58:22:20 % ) were significantly different . Dietary energy was restricted , but was slightly higher during the VLCK ( 1855 kcal/day ) compared to the LF ( 1562 kcal/day ) diet for men . Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss , total fat loss , and trunk fat loss for men ( despite significantly greater energy intake ) . The majority of women also responded more favorably to the VLCK diet , especially in terms of trunk fat loss . The greater reduction in trunk fat was not merely due to the greater total fat loss , because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and  women . Absolute REE ( kcal/day ) was decreased with both diets as expected , but REE expressed relative to body mass ( kcal/kg ) , was better maintained on the VLCK diet for men only . Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet . Conclusion This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss , especially in men . A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinical ly significant but requires further validation . These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution OBJECTIVE : To determine the effect of replacing some dietary carbohydrate with protein , during energy restriction , on weight loss , total energy expenditure ( TEE ) , resting energy expenditure ( REE ) , respiratory quotient ( RQ ) , and the thermic effect of feeding ( TEF ) in subjects with hyperinsulinemia . DESIGN : Parallel , clinical intervention study of 12 weeks energy restriction ( 6.5 MJ/day ) and 4 weeks energy balance ( 8.2 MJ/day ) in two groups of subjects r and omly assigned to either a high-protein ( HP ) diet ( 27 % of energy ( % E ) as protein , 45%E as carbohydrate ) or a lower-protein ( LP ) diet ( 16%E as protein , 57%E as carbohydrate).SUBJECTS : A total of 36 obese nondiabetic volunteers with hyperinsulinemia ( 10 males/26 females , aged 34–65 y , BMI 28–43 kg/m2 , fasting insulin 12–45 mU/l ) . MEASUREMENTS : Body weight and composition , TEE , REE , and RQ were measured at baseline and at week 16 . In addition , the TEF to an HP or LP meal was determined for 3 h , at baseline and at week 16 . RESULTS : After 16 weeks , weight loss was similar in response to each diet ; the overall decrease was 7.9±0.6 kg ( P<0.001 ) , of which 6.8±0.5 kg was fat ( P<0.001 ) . REE fell similarly with each diet ; the overall decrease was 719±106 kJ/day ( P<0.001 ) . The TEF was 2 % greater after the HP than after the LP meal at baseline ( P<0.01 ) and 0.8 % greater at week 16 ( P=0.35 ) . After 16 weeks , the TEF was not reduced in either dietary group . There was no change in TEE after 16 weeks . CONCLUSION : In subjects with hyperinsulinemia an energy-restrictive diet containing an increased protein-to-carbohydrate ratio does not enhance weight loss or significantly affect energy expenditure . Caloric restriction , rather than the macronutrient composition of the diet , is the most important determinant of weight loss BACKGROUND Long-term weight loss and cardiometabolic effects of a very-low-carbohydrate , high-saturated-fat diet ( LC ) and a high-carbohydrate , low-fat diet ( LF ) have not been evaluated under isocaloric conditions . OBJECTIVE The objective was to compare an energy-controlled LC diet with an LF diet at 1 y. DESIGN Men and women ( n = 118 ) with abdominal obesity and at least one additional metabolic syndrome risk factor were r and omly assigned to either an energy-restricted ( approximately 6 - 7 MJ ) LC diet ( 4 % , 35 % , and 61 % of energy as carbohydrate , protein , and fat , respectively ) or an isocaloric LF diet ( 46 % , 24 % , and 30 % of energy as carbohydrate , protein , and fat , respectively ) for 1 y. Weight , body composition , and cardiometabolic risk markers were assessed . RESULTS Sixty-nine participants ( 59 % ) completed the trial : 33 in the LC group and 36 in the LF group . Both groups lost similar amounts of weight ( LC : -14.5 + /- 1.7 kg ; LF : -11.5 + /- 1.2 kg ; P = 0.14 , time x diet ) and body fat ( LC : -11.3 + /- 1.5 kg ; LF : -9.4 + /- 1.2 kg ; P = 0.30 ) . Blood pressure , fasting glucose , insulin , insulin resistance , and C-reactive protein decreased independently of diet composition . Compared with the LF group , the LC group had greater decreases in triglycerides ( -0.36 + /- 0.15 mmol/L ; 95 % CI : -0.67 , -0.05 mmol/L ; P = 0.011 ) , increases in HDL cholesterol ( 0.23 + /- 0.09 mmol/L ; 95 % CI : 0.06 , 0.40 mmol/L ; P = 0.018 ) and LDL cholesterol ( 0.6 + /- 0.2 mmol/L ; 95 % CI : 0.2 , 1.0 mmol/L ; P = 0.001 ) , and a greater but nonsignificant increase in apolipoprotein B ( 0.08 + /- 0.04 g/L ; 95 % CI : -0.004 , 0.171 g/L ; P = 0.17 ) . CONCLUSIONS Under planned isoenergetic conditions , as expected , both dietary patterns result ed in similar weight loss and changes in body composition . The LC diet may offer clinical benefits to obese persons with insulin resistance . However , the increase in LDL cholesterol with the LC diet suggests that this measure should be monitored . This trial was registered with the Australian New Zeal and Clinical Trials Registry at ( http://www.anzctr.org.au ) as ACTR 12606000203550 BACKGROUND Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages . OBJECTIVE The objective was to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition , cardiovascular disease risk , nutritional status , and markers of bone turnover and renal function in overweight women . DESIGN The subjects were r and omly assigned to 1 of 2 isocaloric 5600-kJ dietary interventions for 12 wk according to a parallel design : a high-protein ( HP ) or a high-carbohydrate ( HC ) diet . RESULTS One hundred women with a mean ( + /-SD ) body mass index ( in kg/m(2 ) ) of 32 + /- 6 and age of 49 + /- 9 y completed the study .  Weight loss was 7.3 + /- 0.3 kg with both diets . Subjects with high serum triacylglycerol ( > 1.5 mmol/L ) lost more fat mass with the HP than with the HC diet ( x + /- SEM : 6.4 + /- 0.7 and 3.4 + /- 0.7 kg , respectively ; P = 0.035 ) and had a greater decrease in triacylglycerol concentrations with the HP ( -0.59 + /- 0.19 mmol/L ) than with the HC ( -0.03 + /- 0.04 mmol/L ) diet ( P = 0.023 for diet x triacylglycerol interaction ) . Triacylglycerol concentrations decreased more with the HP ( 0.30 + /- 0.10 mmol/L ) than with the HC ( 0.10 + /- 0.06 mmol/L ) diet ( P = 0.007 ) . Fasting LDL-cholesterol , HDL-cholesterol , glucose , insulin , free fatty acid , and C-reactive protein concentrations decreased with weight loss . Serum vitamin B-12 increased 9 % with the HP diet and decreased 13 % with the HC diet ( P < 0.0001 between diets ) . Folate and vitamin B-6 increased with both diets ; homocysteine did not change significantly . Bone turnover markers increased 8 - 12 % and calcium excretion decreased by 0.8 mmol/d ( P < 0.01 ) . Creatinine clearance decreased from 82 + /- 3.3 to 75 + /- 3.0 mL/min ( P = 0.002 ) . CONCLUSION An energy-restricted , high-protein , low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet OBJECTIVE To evaluate the effects of two low-fat hypocaloric diets differing in the carbohydrate-to-protein ratio , with and without resistance exercise training ( RT ) , on weight loss , body composition , and cardiovascular disease ( CVD ) risk outcomes in overweight/obese patients with type 2 diabetes . RESEARCH DESIGN AND METHODS A total of 83 men and women with type 2 diabetes ( aged 56.1 ± 7.5 years , BMI 35.4 ± 4.6 kg/m2 ) were r and omly assigned to an isocaloric , energy-restricted diet ( female subjects 6 MJ/day , male subjects 7 MJ/day ) of either st and ard carbohydrate ( CON ; carbohydrate : protein : fat 53:19:26 ) or high protein ( HP ; 43:33:22 ) , with or without supervised RT ( 3 days/week ) for 16 weeks . Body weight and composition , waist circumference ( WC ) , and cardiometabolic risk markers were assessed . RESULTS Fifty-nine participants completed the study . There was a significant group effect ( P ≤ 0.04 ) for body weight , fat mass , and WC with the greatest reductions occuring in HP+RT ( weight [ CON : −8.6 ± 4.6 kg , HP : −9.0 ± 4.8 kg , CON+RT : −10.5 ± 5.1 kg , HP+RT : −13.8 ± 6.0 kg ] , fat mass [ CON : −6.4 ± 3.4 kg , HP : −6.7 ± 4.0 kg , CON+RT : −7.9 ± 3.7 kg , HP+RT : −11.1 ± 3.7 kg ] , and WC [ CON : −8.2 ± 4.6 cm , HP : −8.9 ± 3.9 cm , CON+RT : −11.3 ± 4.6 cm , HP+RT : −13.7 ± 4.6 cm ] ) . There was an overall reduction ( P < 0.001 ) in fat-free mass ( −2.0 ± 2.3 kg ) , blood pressure ( −15/8 ± 10/6 mmHg ) , glucose ( −2.1 ± 2.2 mmol/l ) , insulin ( −4.7 ± 5.4 mU/l ) , A1C ( −1.25 ± 0.94 % ) , triglycerides ( −0.47 ± 0.81 mmol/l ) , total cholesterol ( −0.67 ± 0.69 mmol/l ) , and LDL cholesterol ( −0.37 ± 0.53 mmol/l ) , with no difference between groups ( P ≥ 0.17 ) . CONCLUSIONS An energy-restricted HP diet combined with RT achieved greater weight loss and more favorable changes in body composition . All treatments had similar improvements in glycemic control and CVD risk markers CONTEXT Reduced energy expenditure following weight loss is thought to contribute to weight gain . However , the effect of dietary composition on energy expenditure during weight-loss maintenance has not been studied . OBJECTIVE To examine the effects of 3 diets differing widely in macronutrient composition and glycemic load on energy expenditure following weight loss . DESIGN , SETTING , AND PARTICIPANTS A controlled 3-way crossover design involving 21 overweight and obese young adults conducted at Children 's Hospital Boston and Brigham and Women 's Hospital , Boston , Massachusetts , between June 16 , 2006 , and June 21 , 2010 , with recruitment by newspaper advertisements and postings . INTERVENTION After achieving 10 % to 15 % weight loss while consuming a run-in diet , participants consumed an isocaloric low-fat diet ( 60 % of energy from carbohydrate , 20 % from fat , 20 % from protein ; high glycemic load ) , low-glycemic index diet ( 40 % from carbohydrate , 40 % from fat , and 20 % from protein ; moderate glycemic load ) , and very low-carbohydrate diet ( 10 % from carbohydrate , 60 % from fat , and 30 % from protein ; low glycemic load ) in r and om order , each for 4 weeks . MAIN OUTCOME MEASURES Primary outcome was resting energy expenditure ( REE ) , with secondary outcomes of total energy expenditure ( TEE ) , hormone levels , and metabolic syndrome components . RESULTS Compared with the pre-weight-loss baseline , the decrease in REE was greatest with the low-fat diet ( mean [ 95 % CI ] , -205 [ -265 to -144 ] kcal/d ) , intermediate with the low-glycemic index diet ( -166 [ -227 to -106 ] kcal/d ) , and least with the very low-carbohydrate diet ( -138 [ -198 to -77 ] kcal/d ; overall P = .03 ; P for trend by glycemic load = .009 ) . The decrease in TEE showed a similar pattern ( mean [ 95 % CI ] , -423 [ -606 to -239 ] kcal/d ; -297 [ -479 to -115 ] kcal/d ; and -97 [ -281 to 86 ] kcal/d , respectively ; overall P = .003 ; P for trend by glycemic load < .001 ) . Hormone levels and metabolic syndrome components also varied during weight maintenance by diet ( leptin , P < .001 ; 24-hour urinary cortisol , P = .005 ; indexes of peripheral [ P = .02 ] and hepatic [ P = .03 ] insulin sensitivity ; high-density lipoprotein [ HDL ] cholesterol , P < .001 ; non-HDL cholesterol , P < .001 ; triglycerides , P < .001 ; plasminogen activator inhibitor 1 , P for trend = .04 ; and C-reactive protein , P for trend = .05 ) , but no consistent favorable pattern emerged . CONCLUSION Among overweight and obese young adults compared with pre-weight-loss energy expenditure , isocaloric feeding following 10 % to 15 % weight loss result ed in decreases in REE and TEE that were greatest with the low-fat diet , intermediate with the low-glycemic index diet , and least with the very low-carbohydrate diet . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00315354 OBJECTIVE : To test the hypothesis that hyperinsulinemic obese subjects would respond differently to changes in the composition of hypoenergetic diets . DESIGN : A 4-week r and omized dietary intervention trial . SUBJECTS : Thirteen male obese hyperinsulinemic normoglycemic subjects were divided into two groups and fed hypoenergetic diets providing 80 % of their resting energy expenditure ( REE ) . One group received a high-protein diet ( HP ; 45 % protein , 25 % carbohydrates , and 30 % fat as percent of dietary energy ) and the other a high-carbohydrate diet ( HC ; 12 % protein , 58 % carbohydrates and 30 % fat ) . MEASUREMENTS : Anthropometry , body composition , fasting serum insulin and lipids , and REE were performed before and after the feeding period . RESULTS : Weight loss was higher in the HP than HC group ( 8.3±0.7 vs 6.0±0.6 kg , P<0.05 ) . There was a decrease in body fat in both groups , whereas body water decreased significantly more in the HP group . REE decreased more in the HC than the HP group ( −384.3±84.6 vs −132.3±51.0 kcal , P<0.05 ) . Serum total cholesterol , triglycerides and LDL cholesterol decreased significantly to a similar extent in both diet groups , while HDL cholesterol was decreased significantly only in the HP group . Mean fasting insulin decreased significantly in both diet groups and reached the normal range only in the HP group . CONCLUSION : A low-carbohydrate ( LC ) , HP hypoenergetic diet could be the diet composition of choice for a weight-reducing regimen in obese hyperinsulinemic subjects BACKGROUND Some evidence has suggested that a diet with a higher ratio of protein to carbohydrates has metabolic advantages in the treatment of polycystic ovary syndrome ( PCOS ) . OBJECTIVE The objective of this study was to compare the effect of a high-protein ( HP ) diet to a st and ard-protein ( SP ) diet in women with PCOS . DESIGN A controlled , 6-mo trial was conducted in 57 PCOS women . The women were assigned through rank minimization to one of the following 2 diets without caloric restriction : an HP diet ( > 40 % of energy from protein and 30 % of energy from fat ) or an SP diet ( < 15 % of energy from protein and 30 % of energy from fat ) . The women received monthly dietary counseling . At baseline and 3 and 6 mo , anthropometric measurements were performed , and blood sample s were collected . RESULTS Seven women dropped out because of pregnancy , 23 women dropped out because of other reasons , and 27 women completed the study . The HP diet produced a greater weight loss ( mean : 4.4 kg ; 95 % CI : 0.3 , 8.6 kg ) and body fat loss ( mean : 4.3 kg ; 95 % CI : 0.9 , 7.6 kg ) than the SP diet after 6 mo . Waist circumference was reduced more by the HP diet than by the SP diet . The HP diet produced greater decreases in glucose than did the SP diet , which persisted after adjustment for weight changes . There were no differences in testosterone , sex hormone-binding globulin , and blood lipids between the groups after 6 mo . However , adjustment for weight changes led to significantly lower testosterone concentrations in the SP-diet group than in the HP-diet group . CONCLUSION Replacement of carbohydrates with protein in ad libitum diets improves weight loss and improves glucose metabolism by an effect that seems to be independent of the weight loss and , thus , seems to offer an improved dietary treatment of PCOS women CONTEXT Increasing dietary protein relative to carbohydrate and fat enhances weight loss , at least in part by increasing satiety . The mechanism for this is unclear . OBJECTIVE The objective of this study was to compare the effects of isocaloric test meals with differing protein to fat ratios on fasting and postpr and ial ghrelin , insulin , glucose , appetite , and energy expenditure before and after weight loss on the respective dietary patterns . DESIGN The study design was a r and omized parallel design of 12 wk of weight loss ( 6 MJ/d ) and 4 wk of weight maintenance ( 7.3 MJ/d ) with meals administered at wk 0 and 16 . SETTING The study was performed at an out-patient research clinic . PATIENTS AND OTHER PARTICIPANTS Fifty-seven overweight ( body mass index , 33.8 + /- 3.5 kg/m2 ) hyperinsulinemic men ( n = 25 ) and women ( n = 32 ) were studied . INTERVENTIONS High-protein/low-fat ( 34 % protein/29 % fat ) or st and ard protein/high-fat ( 18 % protein/45 % fat ) diets/meals were given . MAIN OUTCOME MEASURES The main outcome measures were weight loss and fasting and postpr and ial ghrelin , insulin , glucose , appetite , and energy expenditure before and after weight loss . RESULTS Weight loss ( 9.2 + /- 0.7 kg ) and improvements in fasting and postpr and ial insulin and glucose occurred independently of diet composition . At wk 0 and 16 , subjects wanted less to eat after the high-protein/low-fat than the st and ard protein/high-fat meal ( P = 0.02 ) . Fasting ghrelin increased ( 157.5 + /- 3.4 pg/ml or 46.6 + /- 1.0 pmol/liter ; P < 0.001 ) , and the postpr and ial ghrelin response improved with weight loss ( P = 0.043 ) independently of diet composition . Postpr and ial hunger decreased with weight loss ( P = 0.018 ) and was predicted by changes in fasting and postpr and ial ghrelin ( r2 = 0.246 ; P = 0.004 ) . Lean mass was the best predictor of fasting ( r2 = 0.182 ; P = 0.003 ) and postpr and ial ghrelin ( r2 = 0.096 ; P = 0.039 ) levels . CONCLUSIONS Exchanging protein for fat produced similar weight loss and improvements in metabolic parameters and ghrelin homeostasis . The reduced appetite observed with increased dietary protein appears not to be mediated by ghrelin homeostasis BACKGROUND Ad libitum , low-carbohydrate diets decrease caloric intake and cause weight loss . It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake . OBJECTIVE We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake . DESIGN Appetite , caloric intake , body weight , and fat mass were measured in 19 subjects placed sequentially on the following diets : a weight-maintaining diet ( 15 % protein , 35 % fat , and 50 % carbohydrate ) for 2 wk , an isocaloric diet ( 30 % protein , 20 % fat , and 50 % carbohydrate ) for 2 wk , and an ad libitum diet ( 30 % protein , 20 % fat , and 50 % carbohydrate ) for 12 wk .  Blood was sample d frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve ( AUC ) for insulin , leptin , and ghrelin . RESULTS Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC . Mean ( + /-SE ) spontaneous energy intake decreased by 441 + /- 63 kcal/d , body weight decreased by 4.9 + /- 0.5 kg , and fat mass decreased by 3.7 + /- 0.4 kg with the ad libitum , high-protein diet , despite a significantly decreased leptin AUC and increased ghrelin AUC . CONCLUSIONS An increase in dietary protein from 15 % to 30 % of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss . This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets OBJECTIVE : To compare the long-term compliance and effects of two low-fat diets differing in carbohydrate to protein ratio on body composition and biomarkers of cardiovascular disease risk in obese subjects with hyperinsulinemia . DESIGN : Outpatient , parallel , clinical intervention study of two groups of subjects r and omly assigned to either a st and ard protein ( SP ; 15 % protein , 55 % carbohydrate ) or high-protein ( HP ; 30 % protein , 40 % carbohydrate ) diet , during 12 weeks of energy restriction ( ∼6.5 MJ/day ) and 4 weeks of energy balance ( ∼8.3 MJ/day ) . Subsequently , subjects were asked to maintain the same dietary pattern for the succeeding 52 weeks with minimal professional support . SUBJECTS : A total of 58 obese , nondietetic subjects with hyperinsulinemia ( 13 males/45 females , mean age 50.2 y , mean body mass index ( BMI ) 34.0 kg/m2 , mean fasting insulin 17.8 mU/l ) participated in the study .  MEASUREMENTS : Body composition , blood pressure , blood lipids , fasting glucose , insulin , CRP and sICAM-1 were measured at baseline and at weeks 16 and 68 . Urinary urea/creatinine ratio was measured at baseline , week 16 and at 3 monthly intervals thereafter . RESULTS : In total , 43 subjects completed the study with similar dropouts in each group ( P=0.76 ) . At week 68 , there was net weight loss ( SP −2.9±3.6 % , HP −4.1±5.8 % ; P<0.01 ) due entirely to fat loss ( P<0.001 ) with no diet effect . Both diets significantly increased HDL cholesterol concentrations ( P<0.001 ) and decreased fasting insulin , insulin resistance , sICAM-1 and CRP levels ( P<0.05 ) . Protein intake was significantly greater in HP during the initial 16 weeks ( P<0.001 ) , but decreased in HP and increased in SP during 52-week follow-up , with no difference between groups at week 68 , indicating poor long-term dietary adherence behaviour to both dietary patterns . CONCLUSION : Without active ongoing dietary advice , adherence to dietary intervention is poor . Nonetheless , both dietary patterns achieved net weight loss and improvements in cardiovascular risk factors Objective To determine the safety and efficacy of altering the ratio of carbohydrate and protein in low-energy diets in conjunction with a popular exercise program in obese women . Design Matched , prospect i ve clinical intervention study to assess efficacy of varying ratios of carbohydrate and protein intake in conjunction with a regular exercise program . Participants One-hundred sixty one sedentary , obese , pre-menopausal women ( 38.5 ± 8.5 yrs , 164.2 ± 6.7 cm , 94.2 ± 18.8 kg , 34.9 ± 6.4 kg·m-2 , 43.8 ± 4.2 % ) participated in this study . Participants were weight stable and not participating in additional weight loss programs . Methods Participants were assigned to either a no exercise + no diet control ( CON ) , a no diet + exercise group ( ND ) , or one of four diet + exercise groups ( presented as kcals ; % carbohydrate : protein : fat ) : 1 ) a high energy , high carbohydrate , low protein diet ( HED ) [ 2,600 ; 55:15:30 % ] , 2 ) a very low carbohydrate , high protein diet ( VLCHP ) [ 1,200 kcals ; 63:7:30 % ] , 3 ) a low carbohydrate , moderate protein diet ( LCMP ) [ 1,200 kcals ; 50:20:30 % ] and 4 ) a high carbohydrate , low protein diet ( HCLP ) [ 1,200 kcals ; 55:15:30 % ] . Participants in exercise groups ( all but CON ) performed a pneumatic resistance-based , circuit training program under supervision three times per week . Measurements Anthropometric , body composition , resting energy expenditure ( REE ) , fasting blood sample s and muscular fitness assessment s were examined at baseline and weeks 2 , 10 and 14 . Results All groups except CON experienced significant reductions ( P < 0.05 – 0.001 ) in waist circumference over 14 weeks . VLCHP , LCHP and LPHC participants experienced similar but significant ( P < 0.05 – 0.001 ) reductions in body mass when compared to other groups . Delta responses indicated that fat loss after 14 weeks was significantly greatest in VLCHP ( 95 % CI : -5.2 , -3.2 kg ) , LCMP ( -4.0 , -1.9 kg ) and HCLP ( -3.8 , -2.1 kg ) when compared to other groups . Subsequent reductions in % body fat were significantly greater in VLCHP , LCMP and HCLP participants . Initial dieting decreased ( P < 0.05 ) relative REE similarly in all groups . All exercise groups significantly ( P < 0.05 ) improved in muscular fitness , but these improvements were not different among groups . Favorable but non-significant mean changes occurred in lipid panels , glucose and HOMA-IR . Leptin levels decreased ( P < 0.05 ) in all groups , except for CON , after two weeks of dieting and remained lower throughout the 14 week program . Exercise participation result ed in significant improvements in quality of life and body image . Conclusion Exercise alone ( ND ) appears to have minimal impact on measured outcomes with positive outcomes apparent when exercise is combined with a hypoenergetic diet . Greater improvements in waist circumference and body composition occurred when carbohydrate is replaced in the diet with protein . Weight loss in all diet groups ( VLCHP , LCMP and HCLP ) was primarily fat and stimulated improvements in markers of cardiovascular disease risk , body composition , energy expenditure and psychosocial parameters Although popular and effective for weight loss , low-carbohydrate , high-protein , high-fat ( Atkins ) diets have been associated with adverse changes in blood and renal biomarkers . High-protein diets low in fat may represent an equally appealing diet plan but promote a more healthful weight loss .  Healthy adults ( n = 20 ) were r and omly assigned to 1 of 2 low-fat ( < 30 % energy ) , energy-restricted groups : high-protein ( 30 % energy ) or high-carbohydrate ( 60 % energy ) ; 24-h intakes were strictly controlled during the 6-wk trial . One subject from each group did not complete the trial due to out-of-state travel ; two subjects in the high-carbohydrate group withdrew from the trial due to extreme hunger . Body composition and metabolic indices were assessed pre- and post-trial . Both diets were equally effective at reducing body weight ( -6 % , P < 0.05 ) and fat mass ( -9 to -11 % , P < 0.05 ) ; however , subjects consuming the high-protein diet reported more satisfaction and less hunger in mo 1 of the trial . Both diets significantly lowered total cholesterol ( -10 to -12 % ) , insulin ( -25 % ) , and uric acid ( -22 to -30 % ) concentrations in blood from fasting subjects . Urinary calcium excretion increased 42 % in subjects consuming the high-protein diet , mirroring the 50 % increase in dietary calcium with consumption of this diet ; thus , apparent calcium balance was not adversely affected . Creatinine clearance was not altered by diet treatments , and nitrogen balance was more positive in subjects consuming the high-protein diet vs. the high-carbohydrate diet ( 3.9 + /- 1.4 and 0.7 + /- 1.7 g N/d , respectively , P < 0.05 ) . Thus , low-fat , energy-restricted diets of varying protein content ( 15 or 30 % energy ) promoted healthful weight loss , but diet satisfaction was greater in those consuming the high-protein diet BACKGROUND : A relatively high percentage of energy intake as protein has been shown to increase satiety and decrease energy efficiency during overfeeding . AIM : To investigate whether addition of protein may improve weight maintenance by preventing or limiting weight regain after weight loss of 5–10 % in moderately obese subjects . DESIGN OF THE STUDY : In a r and omized parallel design , 148 male and female subjects ( age 44.2±10.1 y ; body mass index ( BMI ) 29.5±2.5 kg/m2 ; body fat 37.2±5.0 % ) followed a very low-energy diet ( 2.1 MJ/day ) during 4 weeks . For subsequent 3 months weight-maintenance assessment , they were stratified according to age , BMI , body weight , restrained eating , and resting energy expenditure ( REE ) , and r and omized over two groups . Both groups visited the University with the same frequency , receiving the same counseling on dem and by the dietitian . One group ( n=73 ) received 48.2 g/day additional protein to their diet . Measurements at baseline , after weight loss , and after 3 months weight maintenance were body weight , body composition , metabolic measurements , appetite profile , eating attitude , and relevant blood parameters . RESULTS : Changes in body mass , waist circumference , REE , respiratory quotient ( RQ ) , total energy expenditure ( TEE ) , dietary restraint , fasting blood-glucose , insulin , triacylglycerol , leptin , β-hydroxybutyrate , glycerol , and free fatty acids were significant during weight loss and did not differ between groups . During weight maintenance , the ‘ additional-protein group ’ showed in comparison to the nonadditional-protein group 18 vs 15 en% protein intake , a 50 % lower body weight regain only consisting of fat-free mass , a 50 % decreased energy efficiency , increased satiety while energy intake did not differ , and a lower increase in triacylglycerol and in leptin ; REE , RQ , TEE , and increases in other blood parameters measured did not differ . CONCLUSION : A 20 % higher protein intake , that is , 18 % of energy vs 15 % of energy during weight maintenance after weight loss , result ed in a 50 % lower body weight regain , only consisting of fat-free mass , and related to increased satiety and decreased energy efficiency Background : Weight loss reduces energy expenditure , but the contribution of different macronutrients to this change is unclear . Hypothesis : We tested the hypothesis that macronutrient composition of the diet might affect the partitioning of energy expenditure during weight loss . Design : A sub study of 99 participants from the Preventing Overweight Using Novel Dietary Strategies ( POUNDS LOST ) trial had total energy expenditure ( TEE ) measured by doubly labeled water , and resting energy expenditure ( REE ) measured by indirect calorimetry at baseline and repeated at 6 months in 89 participants . Participants were r and omly assigned to one of four diets with either 15 or 25 % protein and 20 or 40 % fat . Results : TEE and REE were positively correlated with each other and with fat-free mass and body fat , at baseline and 6 months . The average weight loss of 8.1±0.65 kg ( least-square mean±s.e . ) reduced TEE by 120±56 kcal per day and REE by 136±18 kcal per day . A greater weight loss at 6 months was associated with a greater decrease in TEE and REE . Participants eating the high-fat diet ( HF ) lost significantly more fat-free mass ( 1.52±0.55 kg ) than the low-fat ( LF ) diet group ( P<0.05 ) . Participants eating the LF diet had significantly higher measures of physical activity than the HF group . Conclusion : A greater weight loss was associated with a larger decrease in both TEE and REE . The LF diet was associated with significant changes in fat-free body mass and energy expenditure from physical activity compared with the HF diet BACKGROUND Energy restriction is a common therapeutic approach for weight reduction , but the most effective macronutrient distribution of the hypoenergetic diet as well as the role of the metabolic processes involved require further investigations . OBJECTIVE To study the effect of a high protein ( HP ) hypoenergetic diet compared with a high carbohydrate ( HC ) hypoenergetic diet on fuel utilisation changes during the weight loss process in obese women . DESIGN Eleven obese ( BMI > 30 ) women were r and omly assigned to a 10w dietary intervention study comparing HP ( 30 % protein ) or HC ( 55 % carbohydrate ) energy restricted diets providing 30 % energy fat content . Substrate utilisation was evaluated by indirect calorimetry . Body weight and composition ( Bod Pod ) and blood measurements were performed before and after weight loss . RESULTS On average , the individuals on the HP dietary group lost 4.4 kg more than those in the HC program ( p<0.50 ) , which was mainly due to a fat mass loss ( 3.7 kg , p<0.05 ) with no statistical differences in lean body mass reduction . These losses were accompanied by a significant decrease in fasting leptin in the HP group ( -52 % ; P<0.05 ) . On the other h and post-absorptive lipid oxidation decreased in the HC group ( -48 % ) and remained unchanged in the HP groups . CONCLUSIONS The replacement of some dietary carbohydrate by protein in energy restricted diets , improves weight and fat losses and specifically promotes lipid oxidation in the fasting state , without major different in lean body mass depletion CONTEXT Weight loss elicits physiological adaptations relating to energy intake and expenditure that antagonize ongoing weight loss . OBJECTIVE To test whether dietary composition affects the physiological adaptations to weight loss , as assessed by resting energy expenditure . DESIGN , STUDY , AND PARTICIPANTS : A r and omized parallel- design study of 39 overweight or obese young adults aged 18 to 40 years who received an energy-restricted diet , either low-glycemic load or low-fat .  Participants were studied in the General Clinical Research Centers of the Brigham and Women 's Hospital and the Children 's Hospital , Boston , Mass , before and after 10 % weight loss . The study was conducted from January 4 , 2001 , to May 6 , 2003 . MAIN OUTCOME MEASURES Resting energy expenditure measured in the fasting state by indirect calorimetry , body composition by dual-energy x-ray absorptiometry , cardiovascular disease risk factors , and self-reported hunger . RESULTS Resting energy expenditure decreased less with the low-glycemic load diet than with the low-fat diet , expressed in absolute terms ( mean [ SE ] , 96 [ 24 ] vs 176 [ 27 ] kcal/d ; P = .04 ) or as a proportion ( 5.9 % [ 1.5 % ] vs 10.6 % [ 1.7 % ] ; P = .05 ) . Participants receiving the low-glycemic load diet reported less hunger than those receiving the low-fat diet ( P = .04 ) . Insulin resistance ( P = .01 ) , serum triglycerides ( P = .01 ) , C-reactive protein ( P = .03 ) , and blood pressure ( P = .07 for both systolic and diastolic ) improved more with the low-glycemic load diet . Changes in body composition ( fat and lean mass ) in both groups were very similar ( P = .85 and P = .45 , respectively ) . CONCLUSIONS Changes in dietary composition within prevailing norms can affect physiological adaptations that defend body weight . Reduction in glycemic load may aid in the prevention or treatment of obesity , cardiovascular disease , and diabetes mellitus Background This study 's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss . Methods One hundred forty-one sedentary , obese women ( 38.7 ± 8.0 yrs , 163.3 ± 6.9 cm , 93.2 ± 16.5 kg , 35.0 ± 6.2 kg•m-2 , 44.8 ± 4.2 % fat ) were r and omized to either no diet + no exercise control group ( CON ) a no diet + exercise control ( ND ) , or one of four diet + exercise groups ( high-energy diet [ HED ] , very low carbohydrate , high protein diet [ VLCHP ] , low carbohydrate , moderate protein diet [ LCMP ] and high carbohydrate , low protein [ HCLP ] ) in addition to beginning a 3x•week-1 supervised resistance training program . After 0 , 1 , 10 and 14 weeks , all participants completed testing sessions which included anthropometric , body composition , energy expenditure , fasting blood sample s , aerobic and muscular fitness assessment s. Data were analyzed using repeated measures ANOVA with an alpha of 0.05 with LSD post-hoc analysis when appropriate . Results All dieting groups exhibited adequate compliance to their prescribed diet regimen as energy and macronutrient amounts and distributions were close to prescribed amounts . Those groups that followed a diet and exercise program reported significantly greater anthropometric ( waist circumference and body mass ) and body composition via DXA ( fat mass and % fat ) changes . Caloric restriction initially reduced energy expenditure , but successfully returned to baseline values after 10 weeks of dieting and exercising . Significant fitness improvements ( aerobic capacity and maximal strength ) occurred in all exercising groups . No significant changes occurred in lipid panel constituents , but serum insulin and HOMA-IR values decreased in the VLCHP group . Significant reductions in serum leptin occurred in all caloric restriction + exercise groups after 14 weeks , which were unchanged in other non-diet/non-exercise groups . Conclusions Overall and over the entire test period , all diet groups which restricted their caloric intake and exercised experienced similar responses to each other . Regular exercise and modest caloric restriction successfully promoted anthropometric and body composition improvements along with various markers of muscular fitness . Significant increases in relative energy expenditure and reductions in circulating leptin were found in response to all exercise and diet groups . Macronutrient distribution may impact circulating levels of insulin and overall ability to improve strength levels in obese women who follow regular exercise OBJECTIVE To determine the effect of a high-protein ( HP ) weight loss diet compared with a lower-protein ( LP ) diet on fat and lean tissue and fasting and postpr and ial glucose and insulin concentrations . RESEARCH DESIGN AND METHODS Replacing dietary protein for carbohydrate ( CHO ) during energy restriction and weight loss has been effective in sparing lean mass and improving insulin sensitivity in obese subjects but has not been tested in subjects with type 2 diabetes . We compared an HP diet ( 28 % protein , 42 % CHO , 28 % fat [ 8 % saturated fatty acids , 12 % monounsaturated fatty acids , 5 % polyunsaturated fatty acids ] ) with an LP diet ( 16 % protein , 55 % CHO , 26 % fat [ 8 % saturated fatty acids , 11 % monounsaturated fatty acids , 5 % polyunsaturated fatty acids ] ) in 54 obese men and women with type 2 diabetes during 8 weeks of energy restriction ( 1,600 kcal ) and 4 weeks of energy balance . Body composition was determined by dual-energy X-ray absorptiometry at weeks 0 and 12 . RESULTS Overall , weight loss of 5.2 + /- 1.8 kg was achieved independently of diet composition . However , women on the HP diet lost significantly more total ( 5.3 vs. 2.8 kg , P=0.009 ) and abdominal ( 1.3 vs. 0.7 kg , P=0.006 ) fat compared with the women on the LP diet , whereas , in men , there was no difference in fat loss between diets ( 3.9 vs. 5.1 kg ) . Total lean mass decreased in all subjects independently of diet composition . LDL cholesterol reduction was significantly greater on the HP diet ( 5.7 % ) than on the LP diet ( 2.7 % ) ( P < 0.01 ) . CONCLUSIONS Both dietary patterns result ed in improvements in the cardiovascular disease ( CVD ) risk profile as a consequence of weight loss . However , the greater reductions in total and abdominal fat mass in women and greater LDL cholesterol reduction observed in both sexes on the HP diet suggest that it is a valid diet choice for reducing CVD risk in type 2 diabetes BACKGROUND AND AIM Very low carbohydrate ad libitum diets have been shown to enhance weight loss without increasing cardiometabolic risk factors but no kilojoule-controlled trials have been conducted relative to no intervention . The aim of this study was to compare the changes in weight and other cardiovascular risk factors in 3 isocaloric energy-restricted diets to no-intervention control after 1 year . METHODS AND RESULTS One hundred and thirteen subjects ( age 47 ± 10 years , BMI 32 ± 6 kg/m(2 ) with one additional cardiovascular risk factor ) were r and omly allocated to one of three isocaloric diets ( VLC-very low carbohydrate , 60 % fat , 4 % carbohydrate , n=30 ; VLF-very low fat , 10 % fat , n = 30 ; HUF-high unsaturated fat , 30 % fat , n = 30 ) with intensive support for 3 months followed by minimal support for 12 months compared to a control group ( no intervention , n = 23 ) . The estimated weight change was -3.0 ± 0.2 kg for VLC , -2.0 ± 0.1 kg for VLF , -3.7 ± 0.01 kg for HUF and 0.8 ± 0.5 kg for controls ( P=0.065 ) . After correcting for baseline values , decreases in body weight and diastolic blood pressure in the diet groups ( -2.9 ± 5.2 ) were significantly different to the increase in the control group ( 0.8 ± 5.0 ) ( P<0.05 ) . No differences in cardiovascular risk factors were observed between the diet groups . CONCLUSION Significant cardiometabolic risk factor reduction was observed equally with VLC , VLF and HUF diets after 15 months , compared to an exacerbation of risk factors in the control group . At a modest level of adherence , 3 months of intensive support on these dietary patterns confer an improvement in cardiometabolic profile compared to no dietary intervention after 15 months CONTEXT Incidence of insulin resistance ( IR ) in Americans is steadily rising . IR may be ameliorated with < or = 5 % loss in body weight . OBJECTIVE To examine effects of 2 weight-loss diets on body weight and composition in overweight adults with IR . DESIGN Participants r and omly assigned to a high-protein , low-fat ( HPLF ) or a high-carbohydrate , low-fat ( HCLF ) diet for 8 weeks . SETTING All meals prepared and weighed in the metabolic kitchen at Arizona State University . Lunch consumed on-site ; all other meals packaged for home consumption . PATIENTS Twenty overweight , healthy participants with elevated fasting serum insulin ( > or = 15 microU/L ) were recruited . INTERVENTIONS Both diets were low-fat ( 27 % kcal from fat ; < 7 % saturated , < or = 10 % monounsaturated , and < or = 10 % polyunsaturated ) and energy-restricted ( energy levels were 1200 , 1500 , 1700 or 2000 kcal ) ; HPLF : 32 % protein , 41 % carbohydrate ; HCLF : 59 % carbohydrate , 14 % protein . Energy levels were assigned on the basis of participant 's resting metabolic rate . MAIN OUTCOME MEASURES Body composition , etabolic indices , fasting plasma glucose , and insulin . RESULTS No significant differences were found in the main outcome measures between the diets . Body weight ( HPLF : -4.9 kg ; HCLF : -4.0 kg ) and total percent body fat ( HPLF : -1.5 % ; HCLF : -0.4 % ) significantly reduced from baseline to week 8 ( P = .005 and P = .035 , respectively ) . CONCLUSION Both diets promoted > or = 5 % loss in body weight and significantly reduced percent body fat OBJECTIVE To investigate whether protein intake influences the decline in energy expenditure during energy restriction . DESIGN Cross-over study of three diets of 4.2 MJ/d for 7 days : one diet with 36 % energy as protein and two with 15 % energy as protein , one high in carbohydrate and the other high in fat . SUBJECTS Two men and six women aged 31 - 57 y. BMI 27.B-34.1 kg/m2 . MEASUREMENTS 24-h energy expenditure ( 24-h EE ) , sleeping metabolic rate ( SMR ) and body weight on days 0 and 7 of each diet ; 24-h urinary nitrogen excretion ( 24-h UN ) on days 0 - 7 of each diet . RESULTS 24-h EE and SMR declined on all three diets but the decrease was significantly less on the high protein diet than on the two low protein diets .  Weight loss was similar on all three diets . 24-h UN was less than N intake on the high protein diet but greater than N intake on the two low protein diets . CONCLUSIONS Maintaining protein intake reduces the decrease in energy expenditure during energy restriction
Compared with an energy-restricted SP diet , an isocalorically prescribed HP diet provides modest benefits for reductions in body weight , FM , and triglycerides and for mitigating reductions in FFM and REE
BACKGROUND It is currently unclear whether altering the carbohydrate-to-protein ratio of low-fat , energy-restricted diets augments weight loss and cardiometabolic risk markers .
OBJECTIVE The objective was to conduct a systematic review and meta- analysis of studies that compared energy-restricted , isocaloric , high-protein , low-fat ( HP ) diets with st and ard-protein , low-fat ( SP ) diets on weight loss , body composition , resting energy expenditure ( REE ) , satiety and appetite , and cardiometabolic risk factors .