Different Effects on Hepatic Lipid Metabolism of Low Carbohydrate Diet on Obese and Non-Obese Mice

Aim: The safety and efficacy of a low-carbohydrate (LC) diet in obese and non-obese conditions are not fully understood. This study investigated the effects of a moderate LC diet (40% carbohydrate diet) on metabolic conditions in obese and non-obese mice using hepatic mRNA expression profiles and protein expression of metabolic-related enzymes. Methods: C57BL/6J male mice were fed an eight-week high-fat diet to induce obesity. Non-obese mice were fed a control diet for the same period. Then, both the obese mice and non-obese mice were fed an LC diet (PFC energy ratio: 40, 16, 44) and control diet (PFC energy ratio: 20, 16, 64) for 13 weeks. Results: The obese mice on the LC diet had significantly lower bodyweight gain and visceral adipose tissue weight than those that were on the control diet. In the hepatic mRNA expression metabolic profiles, obese mice on the LC diet had increased Sirt1expressionand decreased Fabp4, Gpx1, and Sod1expression. In addition, obese mice on the LC diet had significantly up regulated acetyl-CoA carboxylase (ACC) phosphorylation than those on the control diet. In the non-obese mice, there were no differences between mice on the LC diet and those on the control diet; however, the non-obese mice on the LC diet tended to have decreased phosphorylated ACC and AMP-activated protein kinase (AMPK). Conclusion: The effects of an LC diet varied according to the state of obesity at the time of implementation, suggesting that up regulated lipid metabolism occurs only in obese conditions.