ENERGY-EXPENDITURE AND NET SUBSTRATE UTILIZATION IN MEN INGESTING USUAL AND HIGH AMOUNTS OF NONSTARCH POLYSACCHARIDE

Background: Diets intrinsically high in nonstarch polysaccharides (NSP s) are frequently advised for body weight regulation and health, but t he consequences for energy expenditure and fuel selection are undeterm ined. Objective: We determined whether energy expenditure and fuel sel ection differ when men consume a diet intrinsically higher in NSP than a usual mixed diet. Design: A randomized crossover design was used in which 12 healthy men were fed a maintenance diet for approximate to 3 wk in a metabolic suite. By judicial choice of food exchanges, the us ual- and hign-NSP diets were similar in protein, fat, and carbohydrate contents. Twenty-four-hour, indirect, open-circuit calorimetry was pe rformed, including measurements of total hydrogen gas and methane. Par ticipants were weight stable (within 2 kg for 3 wk), entered an 11-m(3 ) calorimetry chamber for 36 h with measurements taken in the last 24 h, and underwent a strictly controlled program of moderate physical ac tivity (1.3 x basal metabolic rate). Results: The mean total 24-h ener gy expenditure and percentages from protein, fat, and carbohydrate met abolism were 10 MJ/d and 16%, 35%, and 48%, respectively. Differences (mean +/- SEM) between the 2 diets were only -0.005 +/-. 0.130 MJ/d, - 0.3 +/- 1.3%, -0.2 +/- 2.0%, and 0.6 +/- 2.2%, respectively, and were nonsignificant (P > 0.2). Conclusions: There was no thermogenic respon se to the high NSP diet, which would be advantageous for body weight c ontrol, and no short-term influence on body composition, as may be jud ged from a lack of change in protein, fat, or carbohydrate metabolism.