Weight loss for a healthy liver

Overweight and obesity undoubtedly drive the prevalence of nonalcoholic fatty liver disease (NAFLD) in the population, promoting liver fat accumulation. There is also evidence that obesity may increase disease progression to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and eventually to hepatocellular carcinoma. Hence, weight loss is considered essential in overweight/obese patients with NAFLD to reduce the burden of the disease; even a limited amount of weight loss is associated with decreased hepatic triglyceride content, measured by proton magnetic resonance spectroscopy, and remission of ultrasound-assessed steatosis, in a dose-dependent manner. The possibility to reduce hepatic necroinflammation and fibrosis is less proven, although evidence is rapidly accumulating. A small randomized, controlled trial (RCT), carried out along the principles of cognitive-behavioral therapy, showed that the adoption of healthy lifestyles was accompanied by a significant improvement of necroinflammation and resolution of NASH, compared to a control population (Table 1). Notably, the improvement was driven by weight loss of >7%, irrespective of treatment arm, not by participation in the experimental lifestyle treatment group. Similarly, studies in morbidly obese subjects undergoing bariatric (metabolic) surgery reported histological improvement during follow-up. In summary, there is evidence from the literature that no matter how you lose weight, weight loss improves liver health. In this issue of Gastroenterology, large prospective cohort studies strengthen this evidence.