- control: on one occasion subjects will have received an isocaloric diet (55% carbohydrate, 30% fat, 15% protein) during 4 days. On the morning of the 5th day, they will be studied for 2 hours in basal, postabsorptive conditions and over 6 hours following ingestion of a meal providing ca 10 kcal /kg body weight and containing 55% carbohydrate, 35% fat (of which 15% medium chain triglycerides (MCT) labeled with 13C3 trioctanoate, and 10% protein.