Low-Carb Diet Beats Low-Calorie for Treating Fatty Liver

Loss of excess weight is a mainstay of therapy for nonalcoholic fatty liver disease. A very-low-carb diet works better than a reduced-calorie diet, according to a study in the American Journal of Clinical Nutrition.

Nonalcoholic fatty liver disease (NAFLD) occurs in 20 to 40% of the general population, with most cases occuring between the ages of 40 and 60. It’s an accumulation of triglycerides in the liver. For every week I work in the hospital, I see five or 10 scans (either CT scans or sonograms) that incidentally show fat build-up in the liver.

Nonalcoholic steatohepatitis (NASH) is a subset of NAFLD, perhaps 30% of those with NAFLD. Steatohepatitis involves an inflammatory component, progressing to cirrhosis in 3 to 26% of cases.

Researchers at the University of Texas Southwestern Medical Center assigned 18 obese subjects (average BMI 35) to either a very-low-carb diet (under 20 grams a day) or a low-calorie diet (1200 to 1500 calories a day) for two weeks. Liver fat was measured by magnetic resonance technology. The low-carb groups’ liver fat decreased by 55% compared to 28% in the other group. Weight loss was about the same for both groups (4.6 vs 4 kg).

Bottom Line

This small study needs to be replicated, ideally with a larger group of subjects studied over a longer period. Nevertheless, it appears that a very-low-carb diet may be one of the best dietary approaches to nonalcoholic fatty liver disease. And I bet it’s more sustainable than severe calorie restriction. The Ketogenic Mediterranean Diet, by the way, provides 20-30 grams of carb daily.

Steve Parker, M.D.

Reference: Browning, Jeffrey, et al. Short-term weight loss and hepatic triglyceride reduction: evidence of a metabolic advantage with dietary carbohydrate restriction. Am J Clin Nutr, May 2011 vol. 93 no. 5 1048-1052. doi: 10.3945/ajcn.110.007674