A team from the University of Colorado Health Sciences Center, Denver, USA, examined the effect of the interaction of diet composition and physical inactivity on energy and fat balances.
|Fat balance was greater in subjects who consumed a high-fat diet, as opposed to a high-carbohydrate one.|
|American Journal of Clinical Nutrition|
35 normal-weight and obese subjects were randomly assigned to either a 15-day isoenergetic high-carbohydrate (HC) or high-fat (HF) diet according to a crossover design.
During the first 14 days, body weight and physical activity were maintained. On Day 15, subjects spent 23 hours in a whole-room indirect calorimeter and were fed a diet similar to that consumed during the previous 7 days, while remaining physically inactive.
The researchers found that energy intakes required to maintain body weight stability during the first 14 days were similar between diets.
Normal-weight and obese subjects consuming both diets had a positive energy balance on the sedentary day (Day 15), suggesting that subjects were less active in the calorimeter.
There was no significant effect of diet composition on total energy balance and total protein-energy balance on Day 15; however, carbohydrate balance was more positive with the HC (2497.8 kJ), than with the HF (1159 kJ) diet. Most importantly, fat balance was more positive with the HF (1790.8 kJ) than with the HC (-62.8 kJ) diet.
Researcher Trudy Y Shepard concluded on behalf of the group, "Chronic consumption of a high-carbohydrate diet could provide some protection against body fat accumulation, in persons with a pattern of physical activity that includes frequent sedentary days."