The relationship between substrate oxidation as measured by respiratory exchange ratio (RER) and food intake is undefined. This study is examining the effects of three modulators of substrate oxidation (RER), a glucose preload, exercise and age food intake regulation and net energy balance in normal-weight boys (9-12 y) and men (20-30 y).~Subjects (15 boys, 15 men) were measured in random order with treatments of beverages of either water or glucose followed by either moderate exercise or rest for 40 min. Measures included RER via indirect calorimetry, energy expenditure, subjective appetite, food intake measured at an ad libitum pizza meal and net energy balance as the sum of the calories of the glucose preload + calories from the pizza lunch minus energy expended at exercise or rest.
The purpose of this study is to investigate the effect of substrate oxidation, expressed by RER, on food intake regulation and net energy balance.