Gallbladder motility and gallstone formation in obese patients following very low calorie diets. Use it (fat) to lose it (well)

OBJECTIVE: Dieting obese subjects are at risk of developing gallstones. A gallbladder motor dysfunction could have a pathogenetic role. The principal aim of this study was to evaluate the long term effects of two very low calorie diets differing in fat content on gallbladder emptying and gallstone formation in obese subjects. DESIGN AND SUBJECTS: Gallbladder emptying in response to meals (breakfast, lunch and dinner) in two different diet regimens (3.0 vs 12.2 g of fat/d) was evaluated by ultrasonography in 32 gallstone-free obese patients on different days, before and during (at 45 d intervals) one or two 6-month weight reduction diets (for the first three months: 2.24 MJ (535.2 kcal), 3.0 g fat/d vs 2.415 MJ (577.0 kcal), 12.2 g fat/d; for the second three months, the same low calorie diet of 4.194 MJ (1002 kcal)/d for both groups). In 10 subjects, bile analysis was also performed. RESULTS: Twenty-two (69%) subjects concluded the study, eleven in each group, and a significant weight loss was achieved by all subjects. Gallstones (asymptomatic) developed in 6/11 (54.5%) (P