[Effects of isocaloric diets with different percentage energy from fat on blood glucose and lipids in rats].

OBJECTIVE: To investigate the effects of isocaloric diets with different percentage energy from fat on blood glucose and lipids in rats. METHODS: Forty male SD rats were assigned to low fat group, normal fat group, medium fat group and high fat group using randomized blocks method. Rats in four groups were fed with isocaloric diets whose percentage energy from fat were 5%, 15%, 25% and 40% respectively for 10 weeks. Body weight and body length of rats were measured every week. Blood glucose, blood lipids and insulin were determined at 0, 5th and 10 th week. The perirenal fat and epididymal fat pad were separated and weighed at the end of the 10 th week and the body fat rate was calculated. RESULTS: At the end of the 5th and 10 th week, there were no significant differences among four groups in body weight, Lee's index, body fat rate, insulin and low density lipoprotein cholesterol. At the end of the 10 th week, the level of blood glucose was higher for rats in the high fat group than those in the low fat group( P <0. 01). The level of total cholesterol, triglyceride and high density lipoprotein cholesterol were lower for rats in the high fat group than those in the low fat group( P < 0. 01). The level of blood glucose of the 10 th week was higher for rats in the high fat group than the level at the beginning( P < 0. 05). The level of total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol of the 10 th week was higher for rats in the high fat group than the level at the beginning( P < 0. 01). CONCLUSION: When rats were fed with a isocaloric diet and in the condition of normal growth, diet with high proportion of energy derived from fat would not lead to overweight in rats, whereas it may change the metabolism of blood glucose and lipids.