The Role of Dietary Fat in the Utilization of Protein

Abstract
A study was made of the nutritive properties of a number of fats indigenous to the Pakistani dietary. Ghee, partially hydrogenated cottonseed oil and mustardseed oil were incorporated in a Pakistani-type diet and fed, ad libitum, to weanling rats. The two saturated fats exerted a comparable effect on the rate and efficiency of growth, while the highly unsaturated mustardseed oil was found to inhibit growth and reduce the efficiency of food utilization. The adverse effect of mustardseed oil on growth was attributed to its content of erucic acid. When diets containing ghee, hydrogenated cottonseed oil, mustardseed oil, rapeseed oil, sunflowerseed oil and lard were pair-fed to young adult rats, no differences in nitrogen retention were noted. The fats were absorbed to essentially the same extent. These experiments demonstrate that the protein-sparing property of a fat is independent of its degree of saturation and fatty acid composition. Nitrogen retention was compared under the extreme dietary conditions provided by feeding a fat-free diet and one rich in unsaturated fat (sunflowerseed oil). It was found that, as a source of energy in the diet, fat may be completely replaced with carbohydrate without adversely affecting the utilization of protein. These observations are discussed in relation to the calorie deficiency of the Pakistani dietary.