ACCURATE ENERGY COMPENSATION FOR INTRAGASTRIC AND ORAL NUTRIENTS IN LEAN MALES

Lean healthy males received either parenteral or enteral infusions of pure fat or carbohydrate (2092 kJ), or isotonic saline, to determine t heir influences on food intake and energy regulation in self-selected lunch and dinner meals. In the first study, six males received intrave nous infusions for 3.5 h in the morning, followed by lunch 30 min afte r the infusion ended and dinner 6 h later. No compensation was seen fo r energy differences in intravenous infusions. In the second study, si x males received intragastric infusions for 15 min or 3.5 h. Rapid int ragastric infusions of fat or carbohydrate and slow infusions of fat s ignificantly reduced intake at lunch, whereas slow carbohydrate infusi ons did not. In both studies, subjects reduced intake at lunch 30 min after 2092-kJ yogurt preloads varying in fat and carbohydrate, demonst rating their ability to respond to orally derived energy. These result s support the existence of mechanisms in the gastrointestinal tract fo r the rapid detection of the energy content of ingested nutrients or f oods in lean males.