A small group of both normal weight and overweight boys were studied to measure the amount of food eaten shortly after consuming either a glucose drink or a whey drink.
The glucose drink decreased subsequent food intake for both the normal weight and the overweight boys. The whey drink suppressed food intake better than the glucose drink in the normal weight boys, but not at all for the overweight boys.
The overweight boys may have impaired appetite signalling. Glucose was able to suppress their appetite but protein was not. It does not appear to be related to leptin, since glucose was able to suppress their appetite.