Interactions of Dietary Fiber and Protein on Food Intake and Body Composition of Growing Rats

Abstract

The addition of cellulose to the diet increases protein needs as measured by gains in the fat-free body of ad libitum and pair-fed growing rats. This was attributed to loss of metabolic fecal nitrogen induced by dietary cellulose addition. It was demonstrated that 30% cellulose addition to the diet caused a need for about 1.85% additional dietary crude casein. Rats fed very low protein rations had a larger portion of their gain as fat because their intake of energy was high in relation to protein intake. This excess energy therefore limited an increase in food intake by which the animal might obtain more protein from these low protein rations. When cellulose replaced the energy portion of the diet (sucrose), food intake increased because the animal no longer needed to dispose of the excess energy as body fat or heat. Therefore, protein in low protein rations influences food intake indirectly through its ratio to available dietary energy.