Objective · To explore the effects of low-carbohydrate diet (LCD) on body weight and glycolipid metabolism in obese rats and normal weight rats. Methods · Eighty male normal weight Sprague-Dawley rats were divided randomly into three groups, i.e., normal control diet group (CD group, n10), LCD group (n10) and traditional high-fat diet group (HFD group, n60). After eight weeks, 30 obese rats were selected HFD group. Then the obese rats were divided randomly into three groups. The feed of two groups was changed HFD to LCD (HFD-LCD group) or CD (HFD-CD group), and the rest group was fed with HFD continuously. The experiment lasted for another eight weeks. The feed of CD group and LCD group remained unchanged. The measurement indicators included body weight, feed intake, visceral fat, and blood biochemical indexes (fasting blood glucose, triacylglycerol, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and serum β-hydroxybutyrate concentration). Results · In normal rats, the 6th week, the body weight of LCD group was significantly lower than that of HFD group (PP>0.05). But at the end of the 16th week, total cholesterol of LCD group was significantly higher than that of CD group (P0.001) and high-density lipoprotein cholesterol was lower (P0.021). In the obese rats, at the end of the 16th week, the body weight of HFD-LCD group was significantly lower than that of HFD group and HFD-CD group (PPP>0.05). In the obese rats, compared with HFD group, the intervention of HFD-LCD (β-88.56, P0.000) and HFD-CD (β-39.08, P0.007) resulted in the decrease of body weight. β-hydroxybutyrate level was helpful to weight loss in the range of 1-2 times of HFD-CD group (β-34.92, P0.006). Conclusion · LCD may have different effects on body weight and lipid metabolism between normal weight rats and obese rats, LCD has no weight loss effect on the normal weight rats, but can increase total cholesterol; however, in obese rats LCD can reduce weight and improve the metabolism of glycolipid.