Diet-Induced Thermogenesis: A Comparison of Whole and Processed Foods

This study will examine differences in diet-induced thermogenesis (DIT) between a meal made of processed ingredients and an equivalent, isocaloric meal made of whole ingredients. For the purpose of this study processed foods (PFs) will be considered those that are purchased in a state that is modified from their whole food (WF) counterpart (e.g. shell eggs compared to powdered eggs). Research has shown that less energy is expended to digest processed foods than whole foods, which confers an advantage to processed foods in terms of caloric efficiency, but a disadvantage in terms of energy balance and weight loss. A 2010 study showed that subjects expended approximately 10% less energy to digest sandwiches made of white bread and cheese product compared to sandwiches made of whole grain bread and cheddar cheese. The intent of this study is to enhance those results and improve upon the study design by constructing meals to be more similar in the makeup of individual ingredients, making ingredient processing a more isolated variable. Subjects will be healthy CWU male students with a body mass index of 18.5 - 24.9 kg/m2. Metabolism will be assessed by repeated measurements of resting energy expenditure via indirect calorimetry. Measurements of baseline metabolism will be made; subjects will then be provided one of two meals, both comprised of rice, green beans, and eggs cooked in canola oil and equivalent but differing in processing status (e.g. brown rice and white rice, fresh cooked green beans and canned green beans, etc). Hourly metabolic measurements will be made post-meal for 6 hours. During this time subjects will be asked to minimize non-DIT deviations in metabolism; e.g. those due to physical activity, excitement level, etc. The procedure will be repeated one week later with the other meal so that changes in DIT can be assessed on a subject-by-subject basis. The results of this study will be assessed in the lens of weight loss, specifically dietary choices that affect energy balance. It is possible that consuming a diet that includes more whole foods (versus processed foods) would be beneficial to the attainment of a healthy body weight - either through potential weight loss or weight maintenance.