What is the role of the human gallbladder with respect to weight management?
The human gallbladder is a small sack-like organ that is attached to the liver. Its function is to store a greenish yellow liquid called bile. Bile is an essential part of the digestive system—it emulsifies fats and allows them to be absorbed as energy more easily.
A human can function without a gallbladder. A cholecystectomy is a surgery in which the gallbladder is removed. The gallbladder may be removed for many different reasons, including tumors, gallstones, or gallbladder disease.
Without the gallbladder, a person will not be able to break down fats as easily. Normally, the gallbladder would collect, store and concentrate bile, releasing that bile when a person eats fatty foods. Without the gallbladder, a person still gets bile from the liver, but the bile enters directly into the intestines without becoming concentrated. Without the gallbladder, nutritional deficiencies may develop as a result of the body's inability to digest fat efficiently. When there are large nutritional deficiencies, the body responds by clinging to stores of fat and nutrients. This may result in weight gain because the body's response is to hold on to fats.
The deficiency of certain nutrients causes the body to aggressively store fat, which can certainly result in weight gain. Weight gain is of course a function of several factors, including diet, exercise, and muscle mass. A 1984 British study reported that 87% of men and 68% of women experienced weight gain after cholecystectomy. There is a relationship between gallbladder removal and weight gain. To counteract this effect, cholecystectomy patients can work to maintain a diet that is not nutritionally deficient so that a storage response is not activated within the body.