Postprandial Energy Availability With Three Popular Diets During Weight Maintenance After Weight Loss

We compared the effect of three popular diets on postprandial (PP) metabolism in weight loss maintenance. Participants (n=8 overweight/obese young adults) were fed standard hypocaloric diets to produce 10–15% weight loss, then isocaloric low fat (LF), low glycemic index (LGI) and very low carbohydrate (VLC) diets, each for 1 month in a randomized cross‐over fashion. Participants were studied before and every 30 minutes for 5 hours after test meals. Endpoints were metabolic fuels, energy availability (EA, combined energy density of glucose, free fatty acids [FFA] and & beta‐hydroxybutyrate [BHB]), hormones, metabolic rate (MR), and hunger. Data were analyzed by repeated‐measures ANOVA, with contrasts to compare EA in early and late PP periods. There were significant (p<0.05) diet‐time interactions for glucose, FFA, BHB, insulin, glucagon, and MR, but not cortisol, epinephrine, or hunger. EA differed negligibly during the early PP period (p=0.99) but significantly in the late period (p<0.0001), being lower on LF than LGI or VLC. Future work will examine implications of a LF diet limiting late PP EA for risk of weight regain. Funding: Harvard Medical School, Doris Duke Charitable Foundation, and NIDDK.