Palatability and caloric density as determinants of food intake in hyperphagic and normal rats

Abstract

Female albino rats with lesions of the ventromedial hypothalamus and without any lesions were presented with powdered diets, the caloric density and palatability of which were varied independently by adding kaolin and sodium saccharin or confectioner's sugar. As the dilution of the unsweetened diet increased above 20% the lesioned rats decreased food consumption more than did the controls, and they increased consumption less than did the controls over successive days of exposure to the diluted diets. Sweetening the dilute diets usually produced a larger increase in food consumption among the hyperphagic rats, especially those in the dynamic phase, than among their controls. The data are interpreted in terms of the hypothesis that lesions of the ventromedial hypothalamus remove or attenuate the long term influence of nutritional balance, leaving body weight to be adjusted to a set point defined by the interaction of prevailing values of other stimuli such as diet palatability that are known to influence initiation and termination of eating.