Digestible Energy Determination in Normal Weight and Overweight Females

Summary

Participation Requirements

Description

The obesity epidemic is well documented, and despite a complex etiology influenced by genetic, physiological, psychological, social, behavioral, and environmental factors, obesity seems to be the result of energy imbalance, where energy intake exceeds energy expenditure, regardless of the internal a...

The obesity epidemic is well documented, and despite a complex etiology influenced by genetic, physiological, psychological, social, behavioral, and environmental factors, obesity seems to be the result of energy imbalance, where energy intake exceeds energy expenditure, regardless of the internal and external influences. Studies aiming to quantify and manipulate modulators of energy balance, including gastrointestinal (GI) energy absorption rates (i.e., digestibility), are crucial for reducing the incidence of overweight and obesity and improving overall human health. Despite considerable interindividual variability in the amount of ingested energy that is absorbed (~87-98% of ingested energy) by the gastrointestinal tract, generalized equations are used to calculate individual energy intake requirements, and the factors that contribute to such variability are largely unknown. The proposed study will 1) investigate intra- and interindividual differences in intestinal energy absorption in normal-weight and overweight NHB and NHW females when following a controlled weight maintenance diet and 2) determine factors that mediate and/or predict intestinal absorption efficiency. Females with estimated daily energy requirements of 1890 ± 75 kcal/d will be recruited for this study. Participants will be provided a diet containing 1890 kcal/d [1350 kcal/d*1.4 (activity factor); 55% carbohydrate, 15% protein, 30% fat] for 9 d on 2 occasions (to assess intraindividual variability) separated by at least 3 wk. Participants will collect stool during each feeding phase. Gross energy content (heat combustion by bomb calorimetry) of the diet and stool samples will be used to calculate energy digestibility (diet gross energy - stool gross energy). Factors that may mediate and/or predict energy digestibility efficiency, including gastrointestinal microbial composition, transit time, and gas production, fasting and postprandial metabolites, continuous glucose concentrations, and thermogenesis will be assessed.

Tracking Information