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 .
Orlistat maintains biliary lipid composition and hepatobiliary function in obese subjects undergoing moderate weight loss
OBJECTIVES : Orlistat , an intestinal lipase inhibitor , has recently been approved by the US Food and Drug Administration for treatment of obesity . The effects of orlistat on hepatobiliary function have not been previously defined . A 4 wk study was performed involving modest weight loss in obese subjects to observe any short-term hepatobiliary responses that occur after initiating treatment with orlistat and a hypocaloric diet . METHODS : A total of 23 obese ( BMI 30–41 kg/m2 ) subjects were r and omized to a double blind t.i.d . treatment with 120 mg of orlistat or a placebo in conjunction with a hypocaloric diet ( 1200–1500 kcal/day ) . The study was design ed to achieve similar modest weight loss in both groups in order to be able to directly assess the effects of orlistat .  Cholesterol saturation , bile composition , and gallbladder motility were measured . RESULTS : At the end of the treatment period , mean weight loss of 3.8 kg was achieved in the orlistat group ( vs 2.3 kg with placebo , p = NS ) . Total bile acid concentration decreased significantly with placebo ( –18.57 ± 6.99 mmol/L ; 95 % CI = –32.26 to –4.87 ) , but not with orlistat . Biliary phospholipid concentration decreased significantly with placebo ( −4.38 ± 1.91 mmol/L ; 95 % CI = –8.13 to –0.64 ) but not with orlistat . Mean changes from the baseline in cholesterol saturation index and gallbladder motility were similar in both groups . Microscopy of bile failed to reveal cholesterol microcrystals before or after treatment in either group . CONCLUSIONS : Our findings indicate a primary initial effect of weight loss is a reduction in biliary bile acids and phospholipids . Orlistat blocks these adverse changes in biliary lipid composition and maintains hepatobiliary function . We speculate that the risk of formation of gallstones during weight loss may actually be lowered with orlistat
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 .