Changes in organ growth with feeding pattern. The influence of feeding frequency on the circadian rhythm of protein synthesis in the rat.

The effect of eating one large meal rather than several small meals per day on protein metabolism and the growth of individual organs was investigated in young male rats. Meal-eating did not affect the rate of protein catabolism in liver, kidney, small intestine, or spleen in vivo compared with continously fed control animals that consumed the same total amount of food. A circadian rhythm of protein synthesis was found in liver and kidney slices taken from normal rats killed at various times; starvation reduced the magnitude of protein synthesis but did not alter its cyclical nature. Consumption of the daily food all in one meal distorted the circadian rhythm, particularly when it was taken in the morning, and a morning meal increased the total 24 hour synthesis of protein in liver whereas an evening meal did not. Meal-feeding in the morning increased the weights of the liver, small intestine and tibia compared with continuously fed rats, but meal-feeding in the evening did not.