Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .
Effect of orlistat on fecal fat, fecal biliary acids, and colonic cell proliferation in obese subjects.
BACKGROUND & AIMS Orlistat is a weight management agent that selectively inhibits gastrointestinal lipase activity . Because of orlistat 's mode of action , increased fecal fat is presented to the colonic mucosa , and fecal bile acid and free fatty acid composition may be altered during treatment . Our aim was to assess the effect of treatment of obese subjects with orlistat 120 mg 3 times a day for 6 weeks on fecal lipid and bile acid parameters and colonic mucosal cell proliferation . METHODS Twenty-four obese ( body mass index , 30 - 40 kg/m2 ) but otherwise healthy male and female subjects were enrolled in a single-center , r and omized , double-blind , placebo-controlled  , parallel-group study . Participants were hospitalized during days 1 - 3 and 33 - 42 of treatment and were treated as out patients for the remaining days . RESULTS Treatment with orlistat for 6 weeks result ed in significantly greater increases in fecal weight , total fecal fat , and fecal free fatty acids than placebo .  Total fecal bile acid amounts decreased slightly with orlistat , and increased significantly with placebo treatment ( P < .05 between-group difference ) . Orlistat did not alter colonic cell proliferation as assessed by the 3 proliferative indices ( 5-bromo-2-deoxyuridine , whole crypt mitotic count , and proliferating cell nuclear antigen ) . CONCLUSIONS Biochemical changes in fecal composition related to the pharmacodynamic mode of action of orlistat are not accompanied by altered colonic cell proliferation , a putative biomarker of colon cancer risk
Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .