Food intake in rats is unaffected by the profile of dietary essential fatty acids

Food intake may be differentially responsive to the type of fat in the diet. The present investigation sought to evaluate the energy intake of rats maintained on either a low-fat or a high-fat diet mixed with an oil rich in either linoleic (18:2; n-6; safflower oil) or linolenic (18:3; n-3; flaxseed oil) acid. In Experiment 1, rats (n=28) consumed low-fat versions of either the safflower oil diet or the flaxseed oil diet, each at 9.28% fat (wt/wt). In Experiment 2, different rats (n=28) consumed high-fat versions of these diets, each at 23.6% fat (wt/wt). Within each experiment, the energy intake of rats receiving the safflower oil diet was compared to the energy intake of rats receiving the flaxseed oil diet. Food intake was measured under short-term, long-term and food-deprived conditions. In Experiment 1, short-term energy intakes were not different between the groups, thus demonstrating equal acceptance of the test diets. There were no consistent differences in long-term energy intakes between the safflower group and the flaxseed group. In addition, there were no differences in energy intake under the food-deprivation condition. Results from Experiment 2 paralleled those of Experiment 1. Taken together, the present results suggest that the essential fatty acid profile of the maintenance diet does not influence food intake when nutritive oils are the predominant fatty acid source.