Gallstones and Gastric Bypass
Gallstones are common among obese patients who lose weight rapidly after gastric bypass surgery. Gallstones are not a complication of the surgery as such, but are related to the problem of clinically severe obesity, in general.
Patients who had their gallbladder removed, either before or at the time of gastric bypass, may still develop stones in the remaining bile tubes.
One study found that more than a third (38 percent) of patients who had gastric bypass surgery developed gallstones afterward. Gallstones are most likely to occur within the first few months after surgery.
Gallstones are one of the most medically important complications of voluntary weight loss. People who lose a lot of weight rapidly are at greater risk for developing gallstones. This is very true for us as a WLS patient.
One major study found that people who lost from 9 to 22 pounds (over a 2-year period) were 44 percent more likely to develop gallstones than people who did not lose weight. Those who lost more than 22 pounds were almost twice as likely to develop gallstones.
Other studies have shown that 10 to 25 percent of obese people develop gallstones while on a very-low-calorie diet. (Very-low-calorie diets are usually defined as diets containing 800 calories a day or less.
The food is often in liquid form and taken for a prolonged period, typically 12 to 16 weeks.) The gallstones that developed in people on very-low-calorie diets were usually silent and did not produce any symptoms. However, about a third of the dieters who developed gallstones did have symptoms, and a proportion of these required gallbladder surgery.
In short, the likelihood of a person developing symptomatic gallstones during or shortly after rapid weight loss is about 4 to 6 percent. This estimate is based on reviewing just a few clinical studies, however, and is not conclusive.
Researchers believe 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.
Going for long periods without eating (skipping breakfast, for example), a common practice among dieters, also may decrease gallbladder contractions. If the gallbladder does not contract often enough to empty out the bile, gallstones may form.
A meal or snack containing approximately 10 grams (one-third of an ounce) of fat is necessary for the gallbladder to contract normally. But, no studies have directly linked a diet's nutrient composition to the risk of gallstones.