Very Low Calorie Diet (VLCD)

A very low-calorie diet (VLCD) allows a person who is obese to quickly lose a large amount of weight.

VLCDs usually provide about 800 calories per day in food or liquid form, and are followed for 12 to 16 weeks under the supervision of a health care professional.

Studies have shown that 10 to 25 percent of people on a VLCD developed gallstones.
These gallstones were usually silent, they didn't produce any symptoms. About one-third of the dieters who developed gallstones, however, did have symptoms and some of these required gallbladder surgery.

Experts believe weight-loss dieting may cause a shift in the balance of bile salts and cholesterol in the gallbladder. The cholesterol level is increased and the amount of bile salts is decreased.

Following a diet too low in fat or going for long periods without eating (skipping breakfast, for example), a common practice among dieters, may also decrease gallbladder contractions. If the gallbladder does not contract often enough to empty out the bile, gallstones may form.

A drug called ursodiol that helps dissolve cholesterol in the bile may help prevent gallstones from developing during rapid weight loss. While ursodiol is not approved by the U.S. Food and Drug Administration (FDA) to prevent gallstones, its "off-label" use (the practice of prescribing medications for periods of time or for conditions not FDA-approved) has been shown to be effective and safe. If rapid weight loss is highly likely, you should consider talking with your health care provider about using ursodiol.