Optimizing Low-Carbohydrate Diets to Promote Weight Loss in Mice

Studies have shown the benefits of low-carbohydrate diets on reducing weight in obese subjects. Establishing a mouse model to further evaluate the safety and efficacy of these diets is warranted due to controversial issues about the safety and efficacy of low-carbohydrate diets. In the present study, 40 diet-induced obese mice were split into 5 groups and placed on 1 of 5 diets: a HF diet (HF-HF), a standard chow (SC), three 2% carbohydrate diets with 5% protein (HF-LC5), 10% protein (HF-LC10), and 15% protein (HF-LC5), respectively. 10 mice were fed standard chow (SC-SC) as a non-obese control for whole study. The results showed that the body weights of mice in the HF-LC5, HF-LC10, HF-LC15 and HF-SC groups decreased with time. The most significant decrease in body weight was noted for the HF-LC5 (33%) and HF-SC (23%) mice. Accordingly, the percentage of fat mass decreased in the HF-LC5, HF-LC10, HF-LC15 and HF-SC groups with the most dramatic decrease in fat mass noted for the HF-LC5 and HF-SC groups. Similar energy consumption of low-carbohydrate diet groups to SC-SC group and small percentage of total weight loss in fluid mass suggested limited calorie intake and body water loss did not account for the majority of body weight loss with low-carbohydrate diets. The low-carbohydrate diet groups had increased levels of HDL and urinary ketones, as well as decreased levels of plasma insulin, IGF-1 blood glucose, triglyceride, total cholesterol, and LDL. These results indicate that a diet with 5% protein and 2% carbohydrate can effectively promote weight loss in obese C57BL/6J mice. Future studies with this specially-formulated low-carbohydrate diet should be useful in assessing the long-term safety and effectiveness of low-carbohydrate diets forweight loss using mouse experimental systems.