Overweight and Obesity

Overweight and obesity are both labels for ranges of weight that are greater than what is generally considered healthy for a certain height. The terms also identify ranges of weight that have been shown to increase the likelihood of certain diseases and other health problems.

For adults, overweight and obesity ranges are determined by using weight and height to calculate a number called the "body mass index" (BMI). BMI is an estimate of body fat. It is a good gauge of your risk for diseases that can occur with more body fat.

• An adult who has a BMI between 25 and 29.9 is considered overweight.
• An adult who has a BMI of 30 or higher is considered obese.

See the following table for an example.

It is important to remember that although BMI correlates with the amount of body fat, BMI does not directly measure body fat. As a result, some people, such as athletes, may have a BMI that identifies them as overweight even though they do not have excess body fat. For more information about BMI, visit Body Mass Index.

Use the BMI Calculator or BMI Tables to estimate your body fat.

Overweight and Obesity and Your Health

More than one-third of adults in the United States are obese. Research has shown that as a person's weight increases to reach the levels referred to as overweight and obesity the risks for the following conditions also increases.

• Coronary heart disease
• Type 2 diabetes
• Cancers (endometrial, breast, and colon)
• Hypertension (high blood pressure)
• Dyslipidemia (high total cholesterol or high levels of triglycerides)
• Stroke
• Liver and gallbladder disease
• Sleep apnea and respiratory problems
• Osteoarthritis (a degeneration of cartilage and its underlying bone within a joint)
• Gynecological problems (abnormal menses, infertility)

The medical care costs of obesity in the United States are high. In 2008 dollars, these costs totaled about $147 billion. Because of the health effects, overweight and obesity pose a major public health challenge.

Exposure and Risk

There are a variety of factors that play a role in obesity. Behavior, environment, and genetic factors may have an effect in causing people to be overweight and obese.

Behavior and Environment

People may make decisions based on their environment or community. For example, a person may choose not to walk to the store or to work because of a lack of sidewalks. Community, home, school, health care, and workplace settings can all influence people's health decisions. Therefore, it is important to create environments in these locations that make it easier to engage in physical activity and eat a healthy diet.

Genetics

Science shows that genetics plays a role in obesity. Genes can directly cause obesity in disorders such as Bardet-Biedl syndrome and Prader-Willi syndrome. However, genes do not always predict future health. Genes and behavior may both be needed for a person to be overweight. In some cases, multiple genes may increase one's susceptibility for obesity and require outside factors; such as abundant food supply or little physical activity.

For more information on the genetics and obesity visit Obesity and Genomics.

Other Factors

Some illnesses may lead to obesity or weight gain. These may include Cushing's disease, and polycystic ovary syndrome. Drugs such as steroids and some antidepressants may also cause weight gain. A doctor is the best source to tell you whether illnesses, medications, or psychological factors are contributing to weight gain or making weight loss hard.

Prevention

There are 3 very important actions you can take to combat being overweight and obesity:

1. Know your BMI
   BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
2. Achieve and maintain a healthy weight
   The key to achieving and maintaining a healthy weight is not about short-term dietary changes. It is about a lifestyle that includes healthy eating, regular physical activity, and balancing the number of calories you consume with the number of calories your body uses. Staying in control of your weight contributes to good health now and as you age.
3. Get regular physical activity
   Regular physical activity helps improve your overall health and fitness, and reduces your risk for many chronic diseases.