2. Materials and Methods
ADVERSE EVENTS
Fourteen participants between the ages of 18 and 25 years with a body mass index (BMI) between 18.5 and 29.9 kg/mThe exogenous ketones used in this study were purchased from KetoneAid (Falls Church, VA, USA) and included a KME and a KMES drink. The drinks provided at each condition were diluted with water to a total volume of 110 mL for blinding and consistency. Participants included in this study had never consumed either ketone drink prior to the study.During the first study visit, baseline measurements of body weight, height, body fat percentage, lean body mass percentage, waist–hip ratio, and personal demographic information (name, sex, age, race, and ethnicity) were recorded from each participant. Body weight was measured using a balance scale, while height was measured using a stadiometer. Body composition was measured using bioelectrical impedance analysis (BIA, Omron, HBF-514C, Kyoto, Japan), while waist and hip measurements were conducted using a cloth tension tape measure. Waist circumference was measured once at the start of this study at the narrowest part of the torso between the umbilicus and xiphoid process. Hip circumference was measured once at the start of this study at the maximal circumference of the gluteus maximus.On the day prior to each study condition, participants were asked to record all food and drink consumed and were encouraged to consume a similar diet before every visit. However, participants were not required to change their typical diet during this study. Participants were asked to fast for 8–12 h prior to each visit with all sessions occurring in the morning before 1100 h and after 0630 h. Participants were also told to avoid vigorous or planned physical activity on the morning of the study procedure to avoid any potential confounding effects of exercise metabolism on the variables of interest.Participants were administered with KME, KMES, or PC after obtaining baseline measurements of R-βHB and glucose (0-min). The PC consisted of stevia, potassium sorbate, natural flavors, and denatonium benzoate mixed in distilled water. While the PC did not perfectly match the taste of KME and KMES, participants were naïve to the taste of either experimental drink and thus blinded to what they were receiving. The research team member administering the drinks did not undergo blinding but did not share responses with participants until the completion of the study. Following ingestion, R-βHB and glucose were measured at 15, 30, 60, and 120 min. Capillary blood was measured using a commercially available ketone meter (Keto-Mojo, Napa, CA, USA), which measures circulating R-βHB and glucose concentrations. At the end of each condition, participants completed a symptom questionnaire to report any adverse events, acceptability, and tolerability.The primary outcomes were circulating R-βHB and glucose concentrations. Temporal responses over time were compared using a five condition (PC, KME5, KME10, KMES5, KMES10, and PC) × time (0, 15, 30, 60, and 120 min) ANOVA with repeated measures on time and condition. Total and incremental area under the curve (AUC) were calculated as previously reported [