Increased Postprandial Metabolic Flexibility is Associated with Higher Body Fat Percentages in Healthy Young Adults

Authors

Nicholas Foreman, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Sahil Rajwade, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Jaiden Bluth, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Lauren C. Skoglund, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Audrey M. Letts, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Loretta DiPietro, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Adam Ciarleglio, Department of Biostatistics, The Milken Institute School of Public Health, George Washington University, Washington D.C.
Matthew D. Barberio, Department of Exercise and Nutrition Sciences, The Milken Institute School of Public Health, George Washington University, Washington D.C.

Document Type

Journal Article

Publication Date

10-27-2025

Journal

American journal of physiology. Endocrinology and metabolism

DOI

10.1152/ajpendo.00235.2025

Keywords

Glucose tolerance; Metabolic health; Postprandial; Substrate oxidation

Abstract

Because higher adiposity is associated with cardiometabolic disease, we assessed the relationship between body composition (body fat percentage; BF%) and postprandial metabolic flexibility (change in RER from fasting). Young adults (n = 27, n = 15 females, BMI = 27.1 ± 4.5; BF% = 30.4 ± 8.7; mean ± SD) without overt pathology completed a 100g oral glucose tolerance test (OGTT). Indirect calorimetry before (fasting) and following (30, 60, 90, 120 min) consumption was used to calculate respiratory exchange ratio (RER) and oxidation of carbohydrates (CHOX) and fats (FOX). Serum and plasma were collected at corresponding time points and analyzed for glucose, insulin, and NEFAs. Two-way repeated measures ANOVA were used to compare data between normal weight and overweight/obesity by BMI. The effect of BF% on postprandial metabolic flexibility was tested via linear mixed models while adjusting for potential confounders. During the OGTT, blood glucose, serum insulin, plasma lactate, RER, and CHOX all significantly increased while plasma NEFAs and whole-body FOX decreased (all p<0.05). BF% modified the relationship between postprandial RER and time (p = 0.019); individuals with higher BF% increase their RER faster and to a greater extent (i.e., greater metabolic flexibility) than those with lower BF%. Body fat percentage is associated with greater postprandial metabolic flexibility during an OGTT in young adults. Despite increased adiposity, metabolic flexibility may be preserved, representing a compensatory adaptation to decreased glucose storage in the postprandial period.

APA Citation

Foreman, Nicholas; Rajwade, Sahil; Bluth, Jaiden; Skoglund, Lauren C.; Letts, Audrey M.; DiPietro, Loretta; Ciarleglio, Adam; and Barberio, Matthew D., "Increased Postprandial Metabolic Flexibility is Associated with Higher Body Fat Percentages in Healthy Young Adults" (2025). GW Authored Works. Paper 8230.
https://hsrc.himmelfarb.gwu.edu/gwhpubs/8230

Department

Public Health Student Works