Hydroxycitrate has long-term effects on feeding behavior, body weight regain and metabolism after body weight loss in male rats

We examined the long-term effect of hydroxycitrate (HCA) on food intake, meal patterns, body weight regain and energy conversion ratio as well as on different blood and liver variables in rats after substantial body weight loss. Rats were fed a 1% (g/100 g) fat diet (81% carbohydrate, 10% protein, 1% fat) or a 12% (g/100 g) fat diet (76% carbohydrate, 9% protein, 12% fat) in two separate experiments. Supplementing both diets with 3% HCA after 10 d of restrictive feeding reduced body weight regain over the whole subsequent period of ad libitum consumption (22 d) and decreased the energy conversion ratio [body weight regain (g)/energy intake (MJ)] at the end of the experiment. Only in rats fed the 12% fat diet, HCA had a long-term suppression of food intake. The anorectic effect occurred predominately during the light phase, and was due mainly to a reduction in numbers of meals. In rats fed the 12% fat diet, HCA had no effect on plasma beta-hydroxybutyrate (BHB), but reduced plasma triacylglycerol and increased liver fat concentration. In rats fed the 1% fat diet, HCA did not affect any metabolic variable examined. Thus, the suppressive effect of HCA on body weight regain, which was maintained for at least 3 wk, appears to be independent of the dietary fat content. Yet, the fat content of the diet seemed to be important for the long-term suppressive effect of HCA on feeding. The fact that HCA did not change plasma BHB concentration does not support a role for increased hepatic fatty acid oxidation in the anorectic effect of HCA.