EXERCISE TRAINING DECREASES BODY-FAT MORE IN SELF-SELECTING THAN IN CHOW-FED RATS

This study was designed to examine the influence of exercise training on body weight gain and feeding pattern in rats placed on a self-selec tion or a chow diet regimen. Adult, male, Wistar rats were submitted t o daily 2-h treadmill exercise for 28 days (about 50% of VO2 max) at t he beginning of the nocturnal period. Two other groups of rats were ex amined during the same time: a sedentary group that was deprived of fo od and water during the training session and a control group without a ny treatment. Food intakes were continuously recorded. For both feedin g regimens, trained rats, relative to their respective controls, showe d at the end of the experiment a reduction in body weight gain due to a reduced body fat deposit. Moreover, white adipose tissue (WAT) mass of self-selecting rats was smaller than in chow-fed rats. Exercise tra ining decreased plasma glucose level in chow-fed rats and plasma insul in level in self-selecting rats. In self-selecting rats, food intake w as slightly increased due to enhanced protein intake during the noctur nal period and fat intake increased both during the nighttime and dayt ime periods, whereas in chow-fed rats, food intake was decreased durin g the daytime period. These results show that, in rats placed on a sel f-selection regimen, exercise training increased fat consumption but r educed WAT. This could be a consequence of an increased lipolytic capa city of adipocytes in self-selecting trained rats. Thus, it appears fr om these results that the diet's carbohydrate-to-fat ratio can be an i mportant parameter in shaping the interaction between exercise and bod y weight. (C) 1997 Elsevier Science Inc.