Segregated Intake of Protein-rich and -free Diets in Two Meals a Day; Its Effect on Growth and Vital Functions in Rats

Growing rats meal-fed for 4 weeks with a 20% or 40% casein diet in the morning (9:00–11:00) and a non-protein diet in the evening (19:00-21:00), or vice versa, were examined for growth and metabolic changes. A pair of groups given the 40% casein diet at one meal and the protein-free diet at the other meal, although becoming a little different from each other in growth, did not significantly differ from the control given only the 20% casein diet at the two meals. A pair of groups alternately given the 20% casein and protein-free diets, although excelling in protein efficiency ratio, were far inferior in growth to the groups given the 40% casein diet at either of the two meals. In any case, the rats with alternation of the diets sufficient and deficient in protein preferred the 20% or 40% casein diet to the protein-free one at whichever feeding time, and had a higher body weight gain when the casein diet was administered in the evening. The differences among these groups in protein intake throughout the exp...