Rapid weight loss is associated with occurrence of sludge and gallstones in 20-30% of patients in a few weeks of initiating the slimming procedures.
If a person loses weight too quickly, the liver secretes extra cholesterol; in addition, there is rapid mobilization of cholesterol from adipose tissue stores.
In fasting associated with severely fat restricted diets, gallbladder contraction is reduced, and the accompanying gallbladder stasis favors gallstone formation.
Enhancing gallbladder emptying by inclusion of a small amount of dietary fat inhibits gallstone formation in patients undergoing rapid weight loss.
Fasting in the short term increases the cholesterol saturation of gallbladder bile and in the longer term, causes gallbladder stasis which can lead to sludge, and eventually gallstone formation.