Effects of the Curves® fitness & weight loss program V: leptin & insulin

216 sedentary women were assigned to an exercise & no diet group (E); an exercise & high calorie diet (HCD) group (2,600 kcals/d for 1 wk at 55% C, 15% P, 30% F; 9 wks at 40% C, 30% P, 30% F; 4 wks at 55% C, 15% P, 30% F); or, a low calorie high carbohydrate (HC), high protein (HP), or very high protein (VHP) diet. Diets were 1,200 kcal/d for 1‐wk and 1,600 kcal/d for 9 wks and contained 30% fat, 40–55% CHO on the HCD and HC diets and 50–63% P on the HP and VHP diets. Subjects participated in a supervised Curves fitness program 3‐d/wk. Fasting blood samples were obtained at 0, 2, & 10 weeks. Data were analyzed by repeated measures ANOVA and are presented as means ± SD changes from baseline for the E, HCD, HC, HP and VHP groups after 2 and 10 wks, respectively. After 2 and 10 weeks, leptin levels significantly decreased (−21.5±31; −17±36 %, p=0.001) with leptin tending to decrease to a greater degree in the diet groups (−9.0±21, −18±26; −7.6±19, −1.4±24; −23.1±27, −18.2±33; −22.2±29, −15.3±38; −26.4±39, −20.9±42 %, p=0.07). Changes in insulin levels tended to decrease after the first 2wk (−12.7±55; −1.5±93 %, p=0.10) with no differences among groups (2.8±43, 17.2±46; 13.1±59, 17.1±76; −9.8±71, 3.6±113; −15.2±53, −16.9±40; −24.1±32, −4.1±112 %, p=0.56). The glucose to insulin ratio significantly increased (41.6±71; 50.2±156 %, p=0.004) with no differences among groups (15.5±58, −0.8±38; 7.2±42, 27.8±95; 38.0±61, 70.4±250; 53.8±95, 56.1±104; 51.1±61, 42.3±63 %, p=0.24). No differences were observed among groups in homeostatic insulin sensitivity although it generally decreased in the diet groups (9.4±45, 15.5±55; 21.2±73, 26.1±85; −11.7±73, 2.2±107; −14.4±60, −15.0±44; −23.3±35, −1.4±119 %, p=0.39). Results indicate that the Curves fitness & weight loss program may help modulate leptin and insulin levels.