Influence of diet composition on nitrogen balance and body composition in meal-eating and nibbling rats

A series of experiments was conducted to evaluate the influence of meal frequency on nitrogen balance and body composition of rats. Rats were either fed 2 hours per 24 or 48 hours (meal-eaters), or pair-fed to meal-eaters with an automated feeding machine (nibblers). Rats weighing approximately 250 g initially, were fed 10%, 20%, or 30% casein, high-carbohydrate diets or a 20% casein high-fat diet for 7 to 8 weeks. Meal-eaters gained essentially the same amount of body weight as the nibblers. Meal-feeding once per 24 or 48 hours did not adversely influence nitrogen balance or the body composition of the rats. In one experiment, smaller rats, weighing approximately 150 g initially, were utilized. Meal-eaters again, retained as much nitrogen as nibblers, and contained less body fat than the nibblers. In these studies, meal-eating did not cause a depression in nitrogen retention or an increase in body fat deposition in rats.