The interrelationship between food intake, body weight and oxygen consumption was analysed at 25 degrees C in growing rats. 3. The experiment was divided into two phases lasting four weeks each. During the first phase the animals were subjected to energy restriction and during the second phase they were allowed ad lib energy intake. Four groups of rats were studied: Control with ad lib food intake and three restricted groups R4, R5, and R6 which received during the first phase 4, 5, and 6 g per day of stock diet in a single meal. 3. The results showed a decrease in body weight and oxygen consumption during the restriction period and a recovering of the latter during the refeeding period, without body weight recovering. 4. It is concluded that an energy conservation mechanism is present during food restriction and for some time after refeeding.
