The increased incidence of gallstones is associated with the current increasing number of obese patients and, furthermore, rapid weight loss can lead to an increased risk of stone formation, and there are conflicting opinions on how to prevent gallstones during weight loss. For this reason, Professor Caroline S. Stokes from the University Medical Center Saarland, Germany, and colleagues conducted a systematic literature review study to investigate the effectiveness of ursodeoxycholic acid and a high-fat diet to prevent gallstone formation during weight loss in adults. The results of the study were published in the journal Clinical Gastroenterology and Hepatology in 07/2014. In this study, Professor Stokes et al. screened randomized controlled trials of non-surgical treatment for gallstone prevention by electronic and manual searches. A total of 13 randomized controlled clinical trials, including 1836 patients who had lost weight through dietary control (8) or bariatric surgery (5), were eventually included in the analysis. These clinical trials compared the effects of ursodeoxycholic acid and high-fat diets on gallstone formation. A meta-analysis was performed using a random effects model, and heterogeneity and bias across studies was assessed by subgroup analysis, sensitivity analysis, regression analysis, and serial analysis. This study found that ursodeoxycholic acid significantly reduced the risk of gallstone formation compared to a control intervention. This effect of ursodeoxycholic acid was more pronounced in diet alone compared to surgical weight loss. In addition, ursodeoxycholic acid also significantly reduced the risk of symptomatic gallstones (treated with cholecystectomy), and Professor Stokes et al. also found that a high-fat diet also reduced the risk of gallstone formation compared to a low-fat diet. This study suggests that the use of ursodeoxycholic acid and a high-fat diet during weight loss may prevent the formation of gallstones.