National Institute of Diabetes and

Digestive and Kidney Diseases

NATIONAL INSTITUTES OF HEALTH

WIN Weight-control Information Network

Dieting and

Gallstones

If you are overweight

or obese, you can

lower your risk for

type 2 diabetes, heart

disease, stroke, and

some forms of cancer

by losing weight.

People who are

overweight are at

greater risk for

developing gallstones

than people who are

at a healthy weight.

When choosing a

weight-loss program,

be aware that the

risk for developing

gallstones increases

with quick weight

loss or a large weight

loss. Gradual weight

loss can lower the

risk for obesityrelated gallstones.

What are gallstones?

Gallstones are clusters of solid material that form in the gallbladder. They are

made mostly of cholesterol. Gallstones may occur as one large stone or as many

small ones. They vary in size and may be as large as a golf ball or as small as a

grain of sand.

Experts estimate that 16 to 22 million people in the United States have

gallstones—as many as one in every 12 Americans. Most people with gallstones

do not know that they have them and experience no symptoms. Painless

gallstones are called silent gallstones. Sometimes gallstones can cause abdominal

or back pain. These are called symptomatic gallstones. In rare cases, gallstones

can cause serious health problems. Symptomatic gallstones result in about

800,000 hospitalizations and more than 500,000 operations each year in the U.S.

What causes gallstones?

Gallstones develop in the

gallbladder, a small pear-shaped

organ beneath the liver on the

right side of the abdomen. The

gallbladder is about 3 inches long

and an inch wide at its thickest

part. It stores and releases bile

into the intestine to help digestion.

Bile is a liquid made

by the liver. It contains water,

cholesterol, bile salts, fats,

proteins, and bilirubin, a bile

pigment. During digestion, the

gallbladder contracts to release bile into the intestine where the bile salts help to

break down fat. Bile also dissolves excess cholesterol.

According to researchers, gallstones may form in one of three ways: when bile

contains more cholesterol than it can dissolve, when there is too much of certain

proteins or other substance in the bile that causes cholesterol to form hard

crystals, or when the gallbladder does not contract and empty its bile regularly.

What are the symptoms of gallstones?

Some common symptoms of gallstones or gallstone attack include:

■ severe pain in the upper abdomen that starts suddenly and lasts from 30

minutes to many hours

■ pain under the right shoulder or in the right shoulder blade

Liver

Gallbladder

Duodenum

Pancreatic

duct

Common bile

duct

Pancreas

Hepatic ducts

Cystic duct
Find your weight on

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up from that point

until you come to the

line that matches

your height. Then

look to find your

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■ nausea or vomiting

■ indigestion after eating high-fat foods, such as fried

foods or desserts

Is obesity a risk factor for gallstones?

Obesity is a strong risk factor for gallstones, especially

among women. People who are obese are more likely to

have gallstones than people who are at a healthy weight.

Body mass index (BMI) can be used to measure obesity in

adults. BMI is calculated from this equation: weight in

pounds x 703, divided by height in inches x height in

inches. The table below calculates BMI for you. A BMI of

18.5 to 24.9 refers to a healthy weight, a BMI of 25 to

29.9 refers to overweight, and a BMI of 30 or higher refers

to obese.

As BMI increases, the risk for developing gallstones also

rises. Studies have shown that risk may triple in women

who have a BMI greater than 32 compared to those with a

BMI of 24 to 25. Risk may increase sevenfold in women

with a BMI greater than 45 compared to those with a BMI

less than 24.

Researchers have found that people who are obese may

produce high levels of cholesterol. This leads to the

production of bile containing more cholesterol than it can

dissolve. When this happens, gallstones can form. People

who are obese may also have large gallbladders that do not

empty normally or completely. Some studies have shown

that men and women who carry fat around their

midsections may be at a greater risk for developing

gallstones than those who carry fat around their hips and

thighs.

Is weight-loss dieting a risk factor for

gallstones?

Weight-loss dieting increases the risk of developing

gallstones. People who lose a large amount of weight

quickly are at greater risk than those who lose weight

more slowly. Rapid weight loss may also cause silent

gallstones to become symptomatic. Studies have shown

that people who lose more than 3 pounds per week may

have a greater risk of developing gallstones than those who

lose weight at slower rates.

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 or less per day in food

or liquid form, and are followed for 12 to 16 weeks under
the supervision of a health care provider. Studies have

shown that 10 to 25 percent of people on a VLCD

developed gallstones. These gallstones were usually

silent—they did not produce any symptoms. About onethird of the dieters who developed gallstones, however, did

have symptoms and some of these required gallbladder

surgery.

Experts 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. 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.

Is weight cycling a risk factor for

gallstones?

Weight cycling, or losing and regaining weight repeatedly,

may increase the risk of developing gallstones. People who

weight cycle—especially with losses and gains of more

than 10 pounds—have a higher risk for gallstones than

people who lose weight and maintain their weight loss. In

addition, the more weight a person loses and regains

during a cycle, the greater the risk of developing

gallstones.

Why weight cycling is a risk factor for gallstones is

unclear. The rise in cholesterol levels during the weight

loss phase of a weight cycle may be responsible.

Is surgery to treat obesity a risk factor for

gallstones?

Gallstones are common among people who undergo

gastrointestinal surgery to lose weight, also called

bariatric surgery. Gastrointestinal surgery to reduce the

size of the stomach or bypass parts of the digestive system

is a weight-loss method for people who have a BMI above

40. Experts estimate that one-third of patients who have

bariatric surgery develop gallstones. The gallstones usually

develop in the first few months after surgery and are

symptomatic.

How can I safely lose weight and decrease

the risk of gallstones?

You can take several measures to decrease the risk of

developing gallstones during weight loss. Losing weight

gradually, instead of losing a large amount of weight

quickly, lowers your risk. Experts recommend losing 1 to

2 pounds per week. You can also decrease the risk of

gallstones associated with weight cycling by aiming for a

modest weight loss that you can maintain. Even a loss of

10 percent of body weight over a period of 6 months or

more can improve the health of an adult who is overweight

or obese.

Your food choices can also affect your gallstone risk.

Experts recommend including some fat in your diet to

stimulate gallbladder contracting and emptying. However,

no more than 30 percent of your total calories should come

from fat. Studies have also shown that diets high in fiber

and calcium may reduce the risk of gallstone development.

Finally, regular physical activity is related to a lower risk

for gallstones.

What is the treatment for gallstones?

Silent gallstones are usually left alone and sometimes

disappear on their own. Symptomatic gallstones are

usually treated. The most common treatment is surgery to

remove the gallbladder. This operation is called a

cholecystectomy. In other cases, drugs are used to dissolve

the gallstones. Your health care provider can help

determine which option is best for you.

Are the benefits of weight loss greater than the risk of

getting gallstones?

Although weight loss increases the risk of developing

gallstones, obesity poses an even greater risk. In addition

to gallstones, obesity is linked to many serious health

problems including:

■ type 2 diabetes

■ high blood pressure

■ heart disease

■ stroke

■ certain types of cancer

■ sleep apnea (when breathing stops for short periods

during sleep)

■ osteoarthritis (wearing away of the joints)

■ gastro-esophageal reflux disease (GERD)

For people who are obese, weight loss can lower the risk

of developing these illnesses. Even a small weight loss of

10 to 20 pounds can improve health and lower disease

risk. In addition, weight loss can bring other benefits such

as better mood and positive self-image.

If you are thinking about starting an eating and physical

activity plan to lose weight, talk with your health care

provider first. Together, you can discuss various eating and

exercise programs, your medical history, and the benefits

and risks of losing weight including the risk of developing

gallstones.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Institutes of Health

NIH Publication No. 02-3677

February 2002

Weight-control

Information

Network

1 WIN WAY

BETHESDA, MD 20892-3665

Phone: (202) 828-1025

FAX: (202) 828-1028

Email: WIN@info.niddk.nih.gov

Internet: www.niddk.nih.gov/

health/nutrit/nutrit.htm

Toll-free number:

1-877-946-4627

The Weight-control Information

Network (WIN) is a national service

of the National Institute of Diabetes

and Digestive and Kidney Diseases

of the National Institutes of Health,

which is the Federal Government’s

lead agency responsible for

biomedical research on nutrition

and obesity. Authorized by Congress

(Public Law 103-43), WIN provides

the general public, health

professionals, the media, and

Congress with up-to-date, sciencebased health information on weight

control, obesity, physical activity,

and related nutritional issues.

WIN answers inquiries, develops and

distributes publications, and works

closely with professional and patient

organizations and Government

agencies to coordinate resources

about weight control and related

issues.

Publications produced by WIN are

carefully reviewed by both NIDDK

scientists and outside experts. This

fact sheet was also reviewed by

Roland Weinsier, M.D., Dr.P.H.,

Professor and Director, Clinical

Nutrition Research Center, University

of Alabama at Birmingham; Arthur

Frank, M.D., The George Washington

University Weight Management

Program; and Henry Pitt, M.D.,

Chair of Surgery, Medical College of

Wisconsin.

This publication is not copyrighted. WIN

encourages users of this fact sheet to duplicate

and distribute as many copies as desired.

This fact sheet is also available at

www.niddk.nih.gov/health/nutrit/nutrit.htm.

Additional Reading

Acalovschi M. “Cholesterol gallstones: From epidemiology to prevention.”

Postgraduate Medicine, 2001: Vol. 77, No. 906, pp. 221-229. This review article,

intended for health professionals, describes the causes, risk factors, and

pathogenesis of gallstones, and provides information on prevention.

Erlinger S. “Gallstones in obesity and weight loss.” European Journal of

Gastroenterology Hepatology, 2000: Vol. 12, No. 12, pp. 1347-1352. This review

article, intended for health professionals, describes the relationships of diet,

weight reduction, and obesity to the development of gallstones. It also describes

the pathophysiology of gallstones and recommendations for treatment and

prevention.

Gallstones. NIH Publication No. 99-2897. This fact sheet provides basic

information about gallstones and treatment options. Published by the National

Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and available

through the National Digestive Diseases Information Clearinghouse (NDDIC), 2

Information Way, Bethesda, MD, 20892-3570, Tel: 1-800-891-5389.

Gastrointestinal Surgery for Severe Obesity. NIH Publication No. 01-4006. This

fact sheet provides basic information about bariatric surgery including benefits

and risks. Published by the National Institute of Diabetes and Digestive and

Kidney Diseases (NIDDK) and available through the Weight-control Information

Network (WIN), 1 WIN Way, Bethesda, MD, 20892-3665, Tel: 1-877-946-4627.

Nutrition and Your Health: Dietary Guidelines for Americans, 2000, 5th Edition.

Published by the United States Department of Agriculture (USDA) and the United

States Department of Health and Human Services (DHHS) and for sale by the

U.S. Government Printing Office, Superintendent of Documents, Mail Stop:

SSOP, Washington, DC 20402-9328, or by calling the Federal Consumer

Information Center at 1-888-878-3256.

Weight Cycling. NIH Publication No. 01-3901. This fact sheet provides general

information about weight cycling and associated health risks. Published by the

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and

available through the Weight-control Information Network (WIN), 1 WIN Way,

Bethesda, MD, 20892-3665, Tel: 1-877-946-4627.

Weight Loss for Life. NIH Publication No. 00-3700. June 2000. Published by the

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and

available through the Weight-control Information Network (WIN), 1 WIN Way,

Bethesda, MD 20892-3665, Tel: 1-877-946-4627.