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Alternative names: Overweight

What is obesity?
What are the signs of obesity?
What causes obesity?
How does my doctor tell if I have obesity?
How is obesity treated?

What is obesity?

Being obese means that you weigh much more than is healthy for your height. Obesity is a growing problem in the United States, and is at the root of many dangerous health conditions, including heart disease, stroke, and type 2 diabetes.

What are the signs of obesity?

An obese person has an excess of body fat. Several measurements can be used to determine obesity. The most common is the body mass index (BMI), which is based on a person's weight and height. An adult with a BMI between 25 and 29.9 is overweight. An adult with a BMI of 30 or higher is considered obese.

Body mass index calculator

Another rule of thumb is that a grown man is considered obese when he weighs 20% or more over the maximum ideal weight for his height. An adult woman is considered obese if she is 25% over her maximum ideal weight. A person who is more than 100 pounds overweight is morbidly obese.

Obesity can lead to many diseases and health conditions, including:

  • High blood pressure
  • High blood cholesterol
  • Type 2 diabetes
  • Heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis
  • Sleep apnea
  • Respiratory problems
  • Some cancers, such as endometrial, breast, and colon cancer

What causes obesity?

Most simply, obesity is caused by eating too many calories and not exercising. But there are other factors not related to diet that can contribute to obesity, including:

  • Genetics. You are more likely to become obese if one or both of your parents are obese.
  • Your metabolism, or the rate at which your body burns the calories you eat. Because everyone's metabolism slows as we age, older people tend to gain weight more quickly than young people. Women often have slower metabolisms than men.
  • Certain medications can cause weight gain, including some antidepressants, drugs used to control seizures, diabetes medications, and birth-control pills
  • Diseases such as diabetes, polycystic ovary syndrome, Cushing's syndrome, and thyroid disorders

How does my doctor tell if I have obesity?

Your doctor will want to do a complete physical examination, and also talk with you about your eating and exercise habits. In addition, he or she will calculate your body mass index to see if you are overweight or obese.

How is obesity treated?



Even moderate weight loss can improve your health, if you are obese. Losing five to ten percent of your body weight can dramatically improve your chances of avoiding obesity-related diseases. Doctors recommend that you plan to lose weight gradually??1/2 to two pounds per week. Other suggestions:

  • Exercise for at least 30 minutes a day, at least three days a week
  • Join a support group of people who are also trying to lose weight
  • Follow a sensible diet. The American Heart Association (AHA) does not recommend a single diet, but instead offers these suggestions:

    • Eat a variety of fruits and vegetables, five or more servings per day
    • Try to eat six or more servings per day of grains, especially whole grains
    • Limit foods that are high in saturated fat, trans-fat and/or cholesterol. These include full-fat milk products, fatty meats, and egg yolks, as well as items that contain tropical oils and partially-hydrogenated vegetable oils.
    • For protein, consume fat-free and low-fat milk products, fish, beans, skinless poultry, and lean meats
    • Choose fats and oils with two grams or less saturated fat per tablespoon. Consider using liquid and tub margarines, canola oil, or olive oil instead of butter.
    • Limit your intake of foods that is high in calories and low in nutrition, like soft drinks and candy
    • Eat less than six grams of salt (2,400 milligrams of sodium) per day
    • Drink alcohol in moderation: no more than one drink a day if you're a woman and no more than two if you're a man


 Gastric bypass surgery is considered for patients who:

  1. Have a body mass index (BMI) over 40
  2. Have a BMI between 35 and 40, and are at high risk for serious obesity-related conditions that could cause death, such as sleep apnea, heart problems, or severe diabetes.
  3. Have physical problems caused by obesity that interfere with lifestyle, or a body size that causes severe problems with work, family role, and walking
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