DIETARY-FAT LEVEL AS AFFECTING RUNNING PERFORMANCE AND OTHER PERFORMANCE-RELATED PARAMETERS OF RATS RESTRICTED OR NON-RESTRICTED IN FOOD-INTAKE

The effect of food energy density on certain physical performance characteristics of rats was studied during ad lib and weight-restricted feeding. After a 16 wk treadmill training period, 48 young adult male Long-Evans rats were divided into 6 groups, receiving 20%, 40% or 70% of energy as dietary fat and fed ad lib or 40% by weight of average ad lib intake. They were run to exhaustion once a week. Increased dietary fat level was not correlated with superior running performance at either food intake level, although during restricted feeding the high fat group received 40% more energy than the low fat group. Lower body weight was correlated with increased running performance at both food intake levels. The rate of performance increase with decreasing body weight during food restriction was significantly higher for the low fat than for the high fat group. Water consumption was considerably lower during restricted than during ad lib feeding. Plasma glucose was lower when the 70% fat diet was fed than when compared to the other fat diets at both levels of food intake. It was lower from day 8 on of restricted than during ad lib food intake, and lower on day 15 than on day 8 of the restricted intake.