Gallstones develop in the gallbladder, a small organ that stores and releases the bile made by the liver. Bile is a dark green fluid containing bile salts and cholesterol. The gallbladder releases bile into the small intestine to assist in digesting fats more efficiently. However, if the bile is contains high concentrations of cholesterol, then stones too difficult for the bile salts to dissolve may develop (1).
Losing weight too quickly or fasting can cause development of gallstones. The quick weight loss and fasting is thought to disturb the balance of bile salts and cholesterol (2;3).
The risk may increase if consuming a diet too low in fat. Avoiding fat reduces frequency of gallbladder emptying. This, in turn, may cause cholesterol to accumulate and lead to greater risk of forming stones (3;4).
1. Dowling RH. Review: pathogenesis of gallstones. Aliment Pharmacol Ther 2000;14 Suppl 2:39-47.
2. Wudel LJ, Jr., Wright JK, Debelak JP, Allos TM, Shyr Y, Chapman WC. Prevention of gallstone formation in morbidly obese patients undergoing rapid weight loss: results of a randomized controlled pilot study. J Surg Res 2002;102:50-6.
3. Festi D, Colecchia A, Orsini M et al. Gallbladder motility and gallstone formation in obese patients following very low calorie diets. Use it (fat) to lose it (well). Int J Obes Relat Metab Disord 1998;22:592-600.
4. Vezina WC, Grace DM, Hutton LC et al. Similarity in gallstone formation from 900 kcal/day diets containing 16 g vs 30 g of daily fat: evidence that fat restriction is not the main culprit of cholelithiasis during rapid weight reduction. Dig Dis Sci 1998;43:554-61.