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Understanding Adult Overweight & Obesity

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Definition & Facts

The terms “overweight” and “obesity” refer to body weight that is greater than what is considered normal or healthy for a certain height. Reaching and staying at a healthy weight can be a long-term challenge for people who are overweight or have obesity.

Factors Affecting Weight & Health

Many factors can affect your weight, leading to overweight, obesity, or extreme obesity. Some of these factors may make it hard for you to lose weight or not regain weight you have lost. Being overweight or having obesity may lead to certain health problems.

Am I at a Healthy Weight?

Knowing your body mass index (BMI) and waist size help tell if you are at a normal or healthy weight; are overweight; have obesity; or have extreme obesity. Your body shape may make you more likely to have certain health problems.

Health Risks

Overweight and obesity may increase your risk for certain health problems and may be linked to certain emotional and social problems.

Eating & Physical Activity

Changing your eating habits is central to losing and maintaining your weight. To lose weight, you have to eat fewer calories and use more calories than you take in. Sticking with an eating plan may be more important than the type of eating plan you follow.


Common treatments for losing weight include healthy eating, being physically active, and making other changes to your usual habits. If you have extreme obesity and related health problems, your doctor may consider other treatments, such as bariatric surgery.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.


Obesity affects more than 1 in 3 adults in the United States. About 1 in 6 children and adolescents ages 2 to 19 are considered to have obesity in the United States. Another 1 in 3 adults is considered to be overweight. View the latest statistics.

Sisters Together

Sisters Together is a health awareness program that encourages black women ages 18 and older to maintain a healthy weight by being more physically active and eating healthy foods.

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Jamy D. Ard, Wake Forest Baptist Health, Wake Forest School of Medicine