Do You Know the 

Health Risks of 

Being Overweight?

WIN Weight-control Information Network

U.S. Department of Health 

and Human Services

NATIONAL INSTITUTES OF HEALTH

What are the risks to my health 

from being overweight?

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.

Body Mass Index 

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 on the following page 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.

If you are overweight, you are 

more likely to 

develop certain 

health problems. 

You may be able 

to improve your 

health by losing 

as little as 10 to 

20 pounds.
2

Body Mass Index Table

Waist Circumference

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.
3

Type 2 Diabetes

What is it?

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.

How is it linked to overweight? 

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.

What can weight loss do? 

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 http://www.diabetes.

niddk.nih.gov/dm/pubs/preventionprogram/index.htm.

Coronary Heart Disease and Stroke

What are they? 

Coronary heart disease means that the heart 

and circulation (blood flow) are not functioning 

normally. Often, the arteries have become hardened 

and narrowed. If you have coronary heart disease, 

you may suffer from a heart attack, congestive heart 

failure, sudden cardiac death, angina (chest pain), 

or abnormal heart rhythm. In a heart attack, the 

flow of blood and oxygen to the heart is disrupted, 

damaging portions of the heart muscle. During a 

stroke, blood and oxygen do not flow normally 

to the brain, possibly causing paralysis or death. 

Coronary heart disease is the leading cause of 

death in the United States, and stroke is the 

third leading cause.

How are they linked to overweight? 

People who are overweight are more likely 

to develop high blood pressure, high levels of 

triglycerides (blood fats) and LDL cholesterol 

(a fat-like substance often called “bad cholesterol”), 

and low levels of HDL cholesterol (“good cholesterol”). These are all risk factors for heart disease 

and stroke. In addition, excess body fat—especially 

abdominal fat—may produce substances that cause 

inflammation. Inflammation in blood vessels and 

throughout the body may raise heart disease risk.

What can weight loss do? 

Losing 5 to 10 percent of your weight can lower 

your chances for developing coronary heart disease 

or having a stroke. If you weigh 200 pounds,

this means losing as little as 10 pounds. Weight 

loss may improve blood pressure, triglyceride, 

and cholesterol levels; improve heart function 

and blood flow; and decrease inflammation 

throughout the body.
4

Metabolic Syndrome

What is it?

The metabolic syndrome is a group of obesityrelated 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.

Cancer

What is it? 

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. 
5

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.

Sleep Apnea

What is it? 

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.

Osteoarthritis

What is it? 

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.

Gallbladder Disease

What is it? 

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. 
6

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.

Fatty Liver Disease

What is it? 

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 at http://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 on page 3). 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.

Pregnancy Complications

What are they?

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.
7

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.

How can I lower my health risks?

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 and keep it off over time, try to 

make long-term changes in your eating and physical 

activity habits. Choose healthy foods, such as 

vegetables, fruits, whole grains, and low-fat meat 

and dairy products more often. Eat just enough 

food to satisfy you. Aim for at least 30 minutes of 

moderate-intensity physical activity, such as walking, on most or all days of the week. To lose weight, 

or to maintain weight loss, you will likely need to 

do more than 30 minutes of moderate physical 

activity daily.

To lose weight and keep 

it off over time, try to make 

long-term changes in your 

eating and physical activity 

habits. 

•	 Choose healthy foods,

such as vegetables, fruits, 

whole grains, and low-fat 

meat and dairy products 

more often. 

•	 Aim for at least 30 minutes

of moderate-intensity 

physical activity, such as 

walking, on most or all 

days of the week.
8

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.

NIH Publication No. 07–4098

November 2004

Updated October 2007

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reviewed by both NIDDK scientists 

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Director, Applied Research Program, 

National Cancer Institute; Robert 

Eckel, M.D., Professor of Medicine, 

Physiology, and Biophysics, University 

of Colorado Health Sciences Center; 

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Director, The George Washington 

University Weight Management 

Program.

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