Effects of different meal compositions after exercise on fat and carbohydrate oxidation in women with different levels of body fat.

We investigated the effects of consuming a high-carbohydrate meal (HC), high-fat meal (HF), or no meal (CON) following exercise on fat and carbohydrate oxidation (FAT-OX, CHO-OX) in women with differing levels of body fat. Healthy, physically active females were divided into a Lower Fat (<25% fat, n = 10) or Higher Fat (>25% fat, n = 9) group and tested on 4 occasions. During session 1, body composition and maximal oxygen consumption were determined. During 3 treatment sessions, subjects preformed treadmill exercise at 55% of maximal oxygen consumption until 350 kcal were expended. At 10 min postexercise subjects consumed a liquid meal standardized to provide energy equal to 20% of 24-h energy expenditure plus the 350 kcal of exercise. The HC meal comprised 64% carbohydrate, 21.6% fat, and 14.4% protein. The HF meal comprised 24% carbohydrate, 62% fat, and 14% protein. CON consisted of water equal to the meal volume. During exercise and 2 h postexercise, expired gases were collected to determine FAT-OX and CHO-OX. During exercise CHO-OX was a significantly higher for the Lower Fat group and FAT-OX was significantly higher for the Lower Fat group for each of the meal conditions. A significant difference was observed across meals (p < 0.05) for CHO-OX (first hour) and for CHO-OX and FAT-OX (second hour) postexercise. There were no significant differences (p > 0.05) between the Lower Fat and Higher Fat groups for either recovery period. In physically active females, the macronutrient composition of the postexercise meal affects substrate oxidation, but the level of body fat does not.