Meal pattern of rats during hyperphagia induced by longterm food restriction is affected by diet composition.

The influence of diet composition on feeding behavior during the hyperphagia induced by about 15% loss in body weight due to restricted feeding (5 g food/day for 7 days) was investigated in adult male rats. Rats were fed either a low-fat, high-carbohydrate diet (LF diet), a medium-fat diet (MF diet) or a carbohydrate-free, high-fat diet (HF diet). The transient hyperphagia resulting from food restriction was greater in LF- and MF-rats than in HF-rats, in which a mild hypophagia was observed following the hyperphagia. Recovery of body weight was imperfect in the HF-rats in comparison to the unrestricted controls. During the hyperphagia, the meal pattern of LF- and MF-rats was mainly characterized by an increase in meal size, whereas HF-rats showed an increase in meal frequency. These observations indicate that control of food intake by body weight in LF- and MF-rats occurs mainly by modulation of the mechanisms producing meal-ending satiety, whereas in HF-rats the mechanisms eliciting meal initiation seem to be affected by body weight.