Caloric compensation in rats with continuous or intermittent access to food

Unpalatability, caloric dilution and brief access all initially depress daily caloric intake. Increasing appetite, decreasing capacity of the food to initiate and to maintain satiety, adaptation of food processing mechanisms, and conditioned increases in meal size subsequently raise intake towards a level which matches caloric input to caloric expenditure (and does not necessarily restore growth to its original trajectory). Food-deprived rats compensate even when access to food is brief, just as freely fed rats do, so long as the adverse factors do not force caloric intake persistently so low that deleterious adaptations and a reinforcement of dietary aversion conditioning begin to operate. Also, when intake is measured over the same short period of time, freely fed rats can be observed to respond to taste at least as strongly as starved rats. Eating for calories is not a set of reactions to some obscure stimulus, on a level with eating for taste, but is the organism's energy balance approaching null point by complex interactions between behavioral control and nutrient processing.