Do You Know the Health Risks
of Being Overweight?

• Body Mass Index Table
• Type 2 Diabetes
• Coronary Heart Disease and Stroke
• Metabolic Syndrome
• Cancer
• Sleep Apnea
• Osteoarthritis
• Gallbladder Disease
• Fatty Liver Disease
• Pregnancy Complications
• How can I lower my health risks?

Weighing too much may increase your risk for developing many health problems. If you are overweight or obese, you may be at risk for:

• type 2 diabetes
• coronary heart disease and stroke
• metabolic syndrome
• certain types of cancer
• sleep apnea
• osteoarthritis
• gallbladder disease
• fatty liver disease
• pregnancy complications

You may be able to lower your health risks by losing weight, doing regular physical activity, and eating healthfully.

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Body Mass Index Table

Body mass index (BMI) is a tool that is often used to determine whether a person’s health is at risk due to his or her weight. BMI is a ratio of your weight to your height. A BMI of 18.5 to 24.9 is considered healthy; a BMI of 25 to 29.9 is considered overweight; and a BMI of 30 or more is considered obese.

You can use the table below to determine your BMI. Find your height in the left-hand column labeled “Height.” Move across to your weight. The number at the top of the column is the BMI for that height and weight. Pounds have been rounded off.

Source: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, September 1998.

* Without Shoes
**Without Clothes

Another way to determine if your weight is placing your health at risk is to measure your waist. Waist measurement does not determine if you are overweight, but it does indicate if you have excess fat in your abdomen. This is important because extra fat around your waist may increase health risks even more than fat elsewhere on your body.

Women with a waist measurement of more than 35 inches and men with a waist measurement of more than 40 inches may have an increased risk for obesity-related diseases.

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Type 2 diabetes is a disease in which blood sugar levels are above normal. High blood sugar is a major cause of coronary heart disease, kidney disease, stroke, amputation, and blindness. In 2002, diabetes was the sixth leading cause of death in the United States.

Type 2 diabetes is the most common type of diabetes in the United States. This form of diabetes is most often associated with old age, obesity, family history of diabetes, previous history of gestational diabetes, and physical inactivity. The disease is more common among certain ethnic populations.

More than 85 percent of people with type 2 diabetes are overweight. It is not known exactly why people who are overweight are more likely to develop this disease. It may be that being overweight causes cells to change, making them resistant to the hormone insulin. Insulin carries sugar from blood to the cells, where it is used for energy. When a person is insulin resistant, blood sugar cannot be taken up by the cells, resulting in high blood sugar. In addition, the cells that produce insulin must work extra hard to try to keep blood sugar normal. This may cause these cells to gradually fail.

You may lower your risk for developing type 2 diabetes by losing weight and increasing the amount of physical activity you do. If you have type 2 diabetes, losing weight and becoming more physically active can help you control your blood sugar levels and prevent or delay complications. Losing weight and exercising more may also allow you to reduce the amount of diabetes medication you take. The Diabetes Prevention Program, a large clinical study sponsored by the National Institutes of Health, found that losing just 5 to 7 percent of your body weight and doing moderate-intensity exercise for 30 minutes a day, 5 days a week, may prevent or delay the onset of type 2 diabetes. For more information about the Diabetes Prevention Program, visit www.diabetes.niddk.nih.gov/dm/pubs/preventionprogram/index.htm.  

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The metabolic syndrome is a group of obesity-related risk factors for coronary heart disease and diabetes. A person has the metabolic syndrome if he or she has three or more of the following risk factors:

• A large waistline. For men, this means a waist measurement of 40 inches or more. For women, it means a waist measurement of 35 inches or more [1].
• High triglycerides or taking medication to treat high triglycerides. A triglyceride level of 150 mg/dL or higher is considered high [1].
• Low levels of HDL (“good”) cholesterol or taking medications to treat low HDL. For men, low HDL cholesterol is below 40 mg/dL. For women, it is below 50 mg/dL [1].
• High blood pressure or taking medications to treat high blood pressure. High blood pressure is 130 mm Hg or higher for systolic blood pressure (the top number) or 85 mm Hg or higher for diastolic blood pressure (the bottom number) [1].
• High fasting blood glucose (sugar) or taking medications to treat high blood sugar. This means a fasting blood sugar of 100 mg/dL or higher [1].

A person with metabolic syndrome has approximately twice the risk for coronary heart disease and five times the risk for type 2 diabetes [1]. It is estimated that 27 percent of American adults have the metabolic syndrome [2].

How is it linked to overweight?

The metabolic syndrome is strongly linked to obesity, especially abdominal obesity. Other risk factors are physical inactivity, insulin resistance, genetics, and old age.

Obesity is a risk factor for the metabolic syndrome because it raises blood pressure and triglycerides, lowers good cholesterol, and contributes to insulin resistance. Excess fat around the abdomen carries even higher risks.

What can weight loss do?

It may be possible to prevent the metabolic syndrome with weight management and physical activity. For patients who already have the syndrome, losing weight and being physically active may help prevent or delay the development of diabetes, coronary heart disease, or other complications.

Individuals who are overweight or obese and who have the metabolic syndrome should aim to lose 10 percent of their body weight and do at least 30 minutes of moderate-intensity physical activity every day. Quitting smoking, eating healthfully, and taking prescription medications for conditions such as high blood pressure or low HDL cholesterol may also be recommended. You can learn more about the metabolic syndrome from the National Heart, Lung, and Blood Institute at http://www.nhlbi.nih.gov.

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Cancer occurs when cells in one part of the body, such as the colon, grow abnormally or out of control. The cancerous cells sometimes spread to other parts of the body, such as the liver. Cancer is the second leading cause of death in the United States.

How is it linked to overweight?

Being overweight may increase the risk of developing several types of cancer, including cancers of the colon, esophagus, and kidney. Overweight is also linked with uterine and postmenopausal breast cancer in women. Gaining weight during adult life increases the risk for several of these cancers, even if the weight gain does not result in overweight or obesity.

It is not known exactly how being overweight increases cancer risk. It may be that fat cells release hormones that affect cell growth, leading to cancer. Also, eating or physical activity habits that may lead to being overweight may also contribute to cancer risk.

What can weight loss do?

Avoiding weight gain may prevent a rise in cancer risk. Healthy eating and physical activity habits may lower cancer risk. Weight loss may also lower your risk, although studies have been inconclusive.

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Sleep apnea is a condition in which a person stops breathing for short periods during the night. A person who has sleep apnea may suffer from daytime sleepiness, difficulty concentrating, and even heart failure.

How is it linked to overweight?

The risk for sleep apnea is higher for people who are overweight. A person who is overweight may have more fat stored around his or her neck. This may make the airway smaller. A smaller airway can make breathing difficult, loud (snoring), or stop altogether. In addition, fat stored in the neck and throughout the body may produce substances that cause inflammation. Inflammation in the neck is a risk factor for sleep apnea.

What can weight loss do?

Weight loss usually improves sleep apnea. Weight loss may help to decrease neck size and lessen inflammation.

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Osteoarthritis is a common joint disorder that causes the joint bone and cartilage (tissue that protects joints) to wear away. Osteoarthritis most often affects the joints of the knees, hips, and lower back.

How is it linked to overweight?

Extra weight may place extra pressure on joints and cartilage, causing them to wear away. In addition, people with more body fat may have higher blood levels of substances that cause inflammation. Inflammation at the joints may raise the risk for osteoarthritis.

What can weight loss do?

Weight loss of at least 5 percent of your body weight may decrease stress on your knees, hips, and lower back, and lessen inflammation in your body. If you have osteoarthritis, losing weight may help improve your symptoms.

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Gallbladder disease includes gallstones and inflammation or infection of the gallbladder. Gallstones are clusters of solid material that form in the gallbladder. They are made mostly of cholesterol and can cause abdominal pain, especially after consuming fatty foods. The pain may be sharp or dull.

How is it linked to overweight?

People who are overweight have a higher risk for developing gallbladder disease. They may produce more cholesterol (a fat-like substance found in the body), a risk factor for gallstones. Also, people who are overweight may have an enlarged gallbladder, which may not work properly.

What can weight loss do?

Fast weight loss (more than 3 pounds per week) or large weight loss can actually increase your chance of developing gallstones. Modest, slow weight loss of about 1/2 to 2 pounds a week is less likely to cause gallstones. Achieving a healthy weight may lower your risk for developing gallstones.

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Fatty liver disease occurs when fat builds up in the liver cells and causes injury and inflammation in the liver. It can sometimes lead to severe liver damage, cirrhosis (build-up of scar tissue that blocks proper blood flow in the liver), or even liver failure. Fatty liver disease is like alcoholic liver damage, but it is not caused by alcohol and can occur in people who drink little or no alcohol. You can learn more about fatty liver disease, also known as nonalcoholic steatohepatitis (NASH), from the National Digestive Diseases Information Clearinghouse www.digestive.niddk.nih.gov/ddiseases/pubs/nash. The NASH Clinical Research Network, sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases, conducts clinical studies about prevention and treatment. For more information on the NASH Clinical Research Network, visit http://www.jhucct.com/nash .

How is it linked to overweight?

People who have diabetes or “pre-diabetes” (when blood sugar levels are higher than normal but not yet in the diabetic range) are more likely to have fatty liver disease than people without these conditions. People who are overweight are more likely to develop diabetes (see the “Type 2 Diabetes” section above). It is not known why some people who are overweight or diabetic get fatty liver disease and others do not.

What can weight loss do?

Losing weight and being physically active can help you control your blood sugar levels. It can also reduce the build-up of fat in your liver and prevent further injury. People with fatty liver disease should avoid drinking alcohol.

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Overweight and obesity raise the risk of pregnancy complications for both mother and baby. Pregnant women who are overweight or obese may have an increased risk for:

• Gestational diabetes (high blood sugar during pregnancy).
• Pre-eclampsia (high blood pressure during pregnancy that can cause severe problems for both mother and baby if left untreated).
• Cesarean delivery or complications with cesarean delivery.

Babies of overweight or obese mothers have an increased risk of neural tube defects (defects of the brain and spinal cord), stillbirth, prematurity, and being large for gestational age.

How are they linked to overweight?

Pregnant women who are overweight are more likely to develop insulin resistance, high blood sugar, and high blood pressure. (Insulin resistance is when cells do not respond properly to the hormone insulin, which carries blood sugar to cells for energy. It may result in high levels of blood sugar.) Overweight also increases the risks associated with surgery and anesthesia, and severe obesity increases operative time and blood loss.

Some studies have shown that gaining excess weight during pregnancy—even without becoming obese—may increase risks. It is important to consult with your obstetrician or other health care provider about how much weight to gain during pregnancy.

What can weight loss do?

Women who are overweight or obese and who would like to become pregnant should speak with their health care provider about losing weight before becoming pregnant. Pre-pregnancy weight loss significantly reduces pregnancy complications. Pregnant women who are overweight or obese should speak with their health care provider about limiting gestational weight gain and being physically active during pregnancy.

Losing excess weight after delivery may help women reduce their health risks. If a woman developed gestational diabetes, losing weight will lower her risk of developing diabetes later in life.

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If you are overweight, losing as little as 5 percent of your body weight may lower your risk for several diseases, including coronary heart disease and type 2 diabetes. If you weigh 200 pounds, this means losing 10 pounds. Slow and steady weight loss of 1/2 to 2 pounds per week, and not more than 3 pounds per week, is the safest way to lose weight.

To lose weight, or to maintain weight loss, you will likely need to do more than 30 minutes of moderate physical activity daily.

For more information, visit the websites below.

National Diabetes Information Clearinghouse
http://www.diabetes.niddk.nih.gov

National Heart, Lung, and Blood Institute
http://www.nhlbi.nih.gov

National Institute of Neurological Disorders and Stroke
http://www.ninds.nih.gov

National Cancer Institute
http://www.cancer.gov

Weight-control Information Network
http://www.win.niddk.nih.gov

Endnotes
[1] Grundy SM, Cleeman JI, Daniels SR, et al. Diagnosis and Management of the Metabolic Syndrome: An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Circulation. October 2005; 1129(17):2735-2752.

[2] Ford ED, Giles WH, Modkad AH. Increasing prevalence of the metabolic syndrome among U.S. adults. Diabetes Care. 2004;24(10):244-9.

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Weight-control Information Network

1 WIN Way
Bethesda, MD 20892–3665
Phone: (202) 828–1025
Toll-free number: 1–877–946–4627
Fax: (202) 828–1028
Email: win@info.niddk.nih.gov
Internet: http://www.win.niddk.nih.gov

The Weight-control Information Network (WIN) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) 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, science-based health information on weight control, obesity, physical activity, and related nutritional issues.

Publications produced by WIN are reviewed by both NIDDK scientists and outside experts. This publication was reviewed by Rachel Ballard-Barbash, M.D., M.P.H., Associate Director, Applied Research Program, National Cancer Institute; Robert Eckel, M.D., Professor of Medicine, Physiology, and Biophysics, University of Colorado Health Sciences Center; and Arthur Frank, M.D., Medical Director, The George Washington University Weight Management Program.

This publication is not copyrighted. WIN encourages users of this brochure to duplicate and distribute as many copies as desired.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
National Institutes of Health

NIH Publication No. 07–4098
November 2004
Updated December 2007

e-text posted: November 2004
e-text updated December 2007