Low-Carbohydrate Diet Versus Caloric Restriction: Effects on Weight Loss, Hormones, and Colon Tumor Growth in Obese Mice

Abstract

Our objective was to compare the effects of a low-carbohydrate diet to a high-carbohydrate/calorie-restricted diet on weight loss, hormones, and transplanted colon tumor growth. Eighty male C57BL/6 mice consumed a diet-induced obesity regimen (DIO) ad libitum for 7 weeks. From Weeks 8 to 14, the mice consumed a 1) DIO diet ad libitum (HF); 2) low-carbohydrate diet ad libitum (LC); 3) high-carbohydrate diet ad libitum (HC); or 4) HC calorie restricted diet (HC–CR). MC38 cells were injected at Week 15. At the time of injection, the HC–CR group displayed the lowest body weight (25.5 ± 0.57 g), serum insulin-like growth factor I (IGF-I; 135 ± 56.0 ng/ml), and leptin (1.0 ± 0.3 ng/ml) levels. This group also exhibited the longest time to palpable tumor (20.1 ± 0.9 days). Compared to the HF group, the HC group exhibited lower body weight (39.4 ± 1.4 vs. 32.9 ± 0.7 g, respectively), IGF-I (604 ± 44.2 vs. 243.4 ± 88.9 ng/ml, respectively), and leptin (15.6 ± 2.2 vs. 7.0 ± 0.7 ng/ml, respectively) levels but similar tumor growth. IGF-I levels were lower in the LC group (320.0 ± 39.9 ng/ml) than the HF group, but tumor growth did not differ. These data suggest LC diets do not slow colon tumor growth in obese mice.