Sources and Mechanisms of Energy Compensation

Excess energy, obesity and obesity-related diseases are important global health issues. Although it is known that obesity is an issue of energy balance, the components of energy expenditure seem to be inter-related in complex non-additive ways. The aim of this study is to explore the downstream impacts of exercise on short term changes in both expenditure and energy intake. The primary question the investigators are asking is whether moderate to high intensity exercise influences the basal energy expenditure and/or energy intake/macronutrient preference in young adult males? (A similar study will be performed on females in a different registration). The investigators will use a specially designed feeding table to measure energy intake and macronutrient intake, which is easy to quantify intake compensation. Basal metabolism will be measured by hood indirect calorimetry. The investigators will explore the factors that influence the level of compensation in expenditure and intake, in particular body composition. Participants will be asked to come to the lab after 10 hours fast for body composition tests including Dual Energy X-ray Absorptiometry(DXA), Magnetic Resonance Image(MRI) and Bioelectrical Impedance Analysis(BIA). They will then be asked (not) to do 30 minutes of moderate-to-vigorous exercise after an energy-limiting breakfast, during which metabolic rate levels and changes in dietary composition will be recorded by gas exchange and standardized buffet. In addition, participants' subjective hunger and preferences will also be recorded by questionnaires. Venous blood will be collected to measure metabolic and hormone factors, blood glucose will be measured by Continuous Blood Glucose Monitor (CGM).