During exercise, the body utilizes fat as a fuel source in a process known as lipolysis. This involves breaking down stored triglycerides into free fatty acids and glycerol, which are then oxidized for energy. Low to moderate-intensity workouts predominantly use fat as fuel, while higher intensity exercise shifts toward carbohydrate utilization. Adequate training enhances the body's ability to efficiently use fat, preserving glycogen stores for prolonged activity. This adaptative response can improve performance and facilitate weight management during regular exercise routines.