To the Editor.
—Causal mechanisms have not been fully clarified to date in several studies that highlight the occurrence of gallstones in obese individuals during weight loss on very low-calorie diets (VLCDs) (Table).1-3 The incidence of new gallstone formation, as detected by ultrasound, ranged from 10% to 26% over 8-week to 16-week periods. Of note is the fact that the diet in each of these studies contained only 1 g of fat. In line with other authors, Liddle et al2 called attention to the possibility of gallbladder stasis as a possible causal factor.The possibility of gallbladder stasis as a primary factor in gallstone formation during weight loss on VLCDs is consistent with the results of a recent study by Festi et al.4 In that study, researchers provided a 500-calorie (2100-J) diet for 13 weeks to 34 obese individuals (mean body mass index, 40.3 kg/m2), followed
Klawansky S, Chalmers TC. Fat Content of Very Low-Calorie Diets and Gallstone Formation. JAMA. 1992;268(7):873. doi:10.1001/jama.1992.03490070051035