Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent liver diseases worldwide, mostly due to the dramatic increase in obesity rates. This disease presents mainly as simple liver steatosis, whereas 10-20% of patients exhibit an inflammatory phenotype referred to as non-alcoholic steatohepatitis (NASH). Advanced liver disease affects a smaller group of patients including fibrosis, cirrhosis and hepatocellular carcinoma. Higher age, extensive overweight, and number of features of the metabolic syndrome are associated with NAFLD severity. In most cases, NAFLD is associated with insulin resistance and insulin resistance is therefore a major target for all NAFLD treatment modalities. Various treatments into this direction, such as the use of thiazolidinediones have recently failed and did not lead to an improvement in liver histology parameters. Successful weight loss either achieved via bariatric surgery or subsequent to lifestyle modification/behavior therapy, however, has been demonstrated to improve both metabolic parameters and liver histology including inflammatory changes. The first recently reported randomized controlled trial in NASH patients testing the effects of weight loss showed that a one year period of lifestyle adjustment resulted in a 7-10% weight loss with significant histological improvement of liver disease. Orlistat, the only available obesity drug treatment on the market, failed to improve insulin resistance or histopathology in NAFLD. Therefore, new weight-loss inducing agents are eagerly awaited to increase the percentage of obese people to benefit from weight reduction.