Frequently Asked Questions

Information provided by the U.S. Department of Health and Human Services

What is the prevalence of overweight and obesity among U.S. adults?

Results of the National Health and Nutrition Examination Survey for 1999–2002 indicate that the following percentages of U.S. adults are overweight or obese:

  • An estimated 30 percent of U.S. adults aged 20 years and older, or over 60 million people, are obese, defined as having a body mass index (BMI) of 30 or higher.
  • An estimated 65 percent of U.S. adults aged 20 years and older are either overweight or obese, defined as having a BMI of 25 or higher.

What is the difference between being overweight and being obese?

Overweight and obesity are both labels for ranges of weight that are greater than what is generally considered healthy for a given 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)

  • 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.

Height Weight Range BMI Considered
5'9" 124 lbs or less below 18.5 Underweight
125 lbs to 168 lbs 18.5 - 24.9 Healthy Weight
169 lbs to 202 lbs 25 - 29.9 Overweight
203 lbs or more 30 or higher Obese

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 children and teens, BMI ranges above a normal weight have different labels (at risk of overweight and overweight). Additionally, BMI ranges for children and teens are defined so that they take into account normal differences in body fat between boys and girls and differences in body fat at various ages.

What are some of the factors that contribute to overweight and obesity?

Researchers have found that several factors can contribute to the likelihood of someone’s becoming overweight or obese.

Behaviors. What people eat and their level of physical activity help determine whether they will gain weight. A number of factors can influence diet and physical activity, including personal characteristics of the individual, the individual’s environment, cultural attitudes, and financial situation.

Genetics. Heredity plays a large role in determining how susceptible people are to becoming overweight or obese. Genes can influence how the body burns calories for energy and how the body stores fat.

How does being overweight or obese affect a person’s health?

When people are or overweight or obese, they are more likely to develop health problems such as the following:

  • Hypertension
  • Dyslipidemia (for example, high total cholesterol or high levels of triglycerides)
  • Type 2 diabetes
  • Coronary heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis
  • Sleep apnea and respiratory problems
  • Some cancers (endometrial, breast, and colon)

The more overweight a person is, the more likely that person is to have health problems. Among people who are overweight and obese, weight loss can help reduce the chances of developing these health problems. Studies show that if a person is overweight or obese, reducing body weight by 5 percent to 10 percent can improve one’s health.

What are the costs associated with overweight and obesity?

According to The Surgeon General’s Call to Action to Prevent and Decrease Overweight and Obesity, the cost of obesity in the United States in 2000 was more than $117 billion ($61 billion direct and $56 billion indirect).

What are some suggestions for losing weight?

Most experts recommend that someone attempting to lose a large amount of weight consult with a personal physician or health care professional before beginning a weight-loss program. The Surgeon General’s Healthy Weight Advice for Consumers makes the following general recommendations:

  • Aim for a healthy weight. People who need to lose weight should do so gradually, at a rate of one-half to two pounds per week.
  • Be active. The safest and most effective way to lose weight is to reduce calories and increase physical activity.
  • Eat well. Select sensible portion sizes and follow the Dietary Guidelines for Americans.

How can physical activity help prevent overweight and obesity?

Physical activity, along with a healthy diet, plays an important role in the prevention of overweight and obesity (USDHHS, 2001). In order to maintain a stable weight, a person needs to expend the same amount of calories as he or she consumes.

Although the body burns calories for everyday functions such as breathing, digestion, and routine daily activities, many people consume more calories than they need for these functions each day. A good way to burn off extra calories and prevent weight gain is to engage in regular physical activity beyond routine activities.

The Energy Balance is like a scale. To remain in balance, the calories consumed (from foods) must be balanced by the calories used (in physical activity).

The Dietary Guidelines for Americans 2005 offers the following example of the balance between consuming and using calories:

If you eat 100 more food calories a day than you burn, you’ll gain about 1 pound in a month. That’s about 10 pounds in a year. The bottom line is that to lose weight, it’s important to reduce calories and increase physical activity.