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 t wo very low calorie diets differing in fat content on gallbladder empt ying and gallstone formation in obese subjects. DESIGN AND SUBJECTS: G allbladder 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 d ays, before and during (at 45 d intervals) one or two 6-month weight r eduction 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 m onths, the same low calorie diet of 4.194 MJ (1002 kcal)/d for both gr oups). In 10 subjects, bile analysis was also performed. RESULTS: Twen ty-two (69%) subjects concluded the study, eleven in each group, and a significant weight loss was achieved by all subjects. Gallstones (asy mptomatic) developed in 6/11 (54.5%) (P<0.01) of subjects following th e lower fat diet, but in none with the higher fat regimen. In the diet ers during the first three months (very low calorie phase) the higher fat meals always induced a significantly greater gallbladder emptying than the lower fat meals. The cholesterol saturation index initially i ncreased significantly and then decreased, without difference between the two groups. CONCLUSION: In the obese during rapid weight loss from a very low calorie diet, a relatively high fat intake could prevent g allstone formation, probably by maintaining an adequate gallbladder em ptying, which could counterbalance lithogenic mechanisms acting during weight toss.