Lack of caloric regulation in rats during short-term feeding

Rats were trained to feed 2 h daily. Each rat was presented during three 10-day-long alimentary periods with each of the following diets: control (C), low calorie (L), and high calorie (H). The food was placed at an ambient temperature of -15 degrees C at 16 m from a warm refuge. It was found that the rats ingested similar amounts of food, regardless of energy density of the diet, and therefore did not compensate for variations in the caloric density of a diet. This was despite the recognition of a novel diet on the first day of its presentation as manifested by a change in rats' meal pattern. L diet was eaten slowly, suggesting that it was less palatable than the C or H diets. The results suggest that the rat placed in a closed economy with only short-term access to food imposed by a hostile environment does not adjust its food intake in accordance with energy value of the food. Its momentary food intake appears to be controlled by the gustatory properties of the food.