Abstract: The high prevalence of obesity has spawned a multimillion dollar industry marketing quick-fix supplements for weight loss. The supplements together with calorie restriction are mainly used by adolescents who wrongly perceive themselves as overweight. Calorie restriction and the supplements may have adverse effects at a critical growth stage. The short term effects of 3 classes of weight loss supplements on growth, the viscera, the exocrine pancreas, hepatic lipids and glycogen, of rats on restricted feed intake was investigated. Forty eight male Sprague Dawley rats were fed standard rat feed ad libitum or restricted to 10% body mass and supplemented with a weight-loss product (carbohydrate blocker, fat blocker or, metabolism booster) for 14 days. Feed restriction significantly (p< 0.01) decreased body mass gain. Restricted feed intake and the weight loss supplements did not significantly (p>0.05) affect GIT morphology, hepatic lipid profile and hepatic glycogen stores, compared to ad libitum feeding. The rats supplemented with carbohydrate blocker had significantly larger testes than the others. The fat blocker significantly increased (p< 0.05) soluble pancreatic proteins. The reduction in body mass gain was due to the feed restriction as opposed to the weight loss products. The fat blocker and carbohydrate blocker potentially have adverse effects in growing male rats.