Effect of palatable hyperlipidic diet on lipid metabolism of sedentary and exercised rats

OBJECTIVE: The present study was designed to examine 1) whether continuous feeding with a palatable hyperlipidic diet and cycling this diet with chow diet would affect lipid and carbohydrate metabolism in a similar way; and 2) whether the effect of chronic exercise on lipid and carbohydrate metabolism would be modified by these diet regimens. METHODS: Male 25-d-old Wistar rats were assigned to one of six groups: sedentary rats fed with chow diet; exercised (swimming 90 min/d, 5 d/wk) rats fed with chow diet; sedentary rats fed with a palatable hyperlipidic diet; exercised rats fed with the palatable hyperlipidic diet; sedentary rats fed with food cycles (four cycles alternating the chow and hyperlipidic diets weekly); and exercised rats fed with food cycles. After 8 wk of treatment, the animals were killed 24 h after the last exercise session. RESULTS: The hyperlipidic diet and food cycles schedules caused similar increases in body weight gain, carcass lipogenesis rate and adiposity, lipid content of the liver and gastrocnemius muscle, and serum total lipid, triacylglycerol, insulin, and leptin levels. The exercise attenuated body weight gain, adipose tissue mass, and serum triacylglycerol, insulin, and leptin levels similarly in the hyperlipidic and food cycles groups. Carcass lipogenesis rate was not affected by exercise in any of the three groups. CONCLUSIONS: The data showed that the continuous intake of a hyperlipidic palatable diet for 8 wk and the alternation of the high-fat intake with periods of chow intake cause obesity and affected lipid metabolism in a similar way. Chronic exercise attenuated body weight gain and adiposity and improved serum lipid concentrations in both high-fat feeding regimens.