Obesity and Weight Loss


Center for Disease Control and Prevention

  • During the past 20 years, obesity among adults has risen significantly in the United States. The latest data from the National Center for Health Statistics show that 30 percent of U.S. adults 20 years of age and older—over 60 million people—are obese.

  • This increase is not limited to adults. The percentage of young people who are overweight has more than tripled since 1980. Among children and teens aged 6–19 years, 16 percent (over 9 million young people) are considered overweight.

  • These increasing rates raise concern because of their implications for Americans’ health. Being overweight or obese increases the risk of many diseases and health conditions, including 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)
  • Definitions for Adults

    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 used because, for most people, it correlates with their amount of 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.

Height Weight Range BMI Considered
5’ 9” 124 lbs or less Below 18.5 Underweight
125 lbs to 168 lbs 18.5 to 24.9 Healthy weight
169 lbs to 202 lbs 25.0 to 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 more information about BMI, visit Body Mass Index.

Other methods of estimating body fat and body fat distribution include measurements of skinfold thickness and waist circumference, calculation of waist-to-hip circumference ratios, and techniques such as ultrasound, computed tomography, and magnetic resonance imaging (MRI).


  • Definitions for Children and Teens

    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. For more information about BMI for children and teens (also called BMI-for-age), visit BMI for Children and Teens.

  • Assessing Health Risks Associated with Overweight and Obesity

    BMI is just one indicator of potential health risks associated with being overweight or obese. For assessing someone’s likelihood of developing overweight- or obesity-related diseases, the National Heart, Lung, and Blood Institute guidelines recommend looking at two other predictors:

  • The individual’s waist circumference (because abdominal fat is a predictor of risk for obesity-related diseases).
  • Other risk factors the individual has for diseases and conditions associated with obesity (for example, high blood pressure or physical inactivity).

American Obesity Association

  • Morbid obesity is defined as having a Body Mass Index (BMI) of 40 or more. This equates to approximately 100 pounds more than ideal weight.  The morbidity and mortality risk from being overweight is proportional to its degree. Individuals with morbid obesity, therefore, have the highest risk for developing numerous illnesses that often reduce mobility and quality of life due to their excess weight. In particular, type 2 diabetes, gallbladder disease and osteoarthritis have been found to increase concurrently with higher BMI. Premature death, a 20-year shorter life span, has also been found in individuals with morbid obesity.

Economic Considerations

Table 1, Aggregate Medical Spending, in Billions of Dollars, Attributable to Overweight and Obesity, by Insurance Status and Data Source, 1996–1998

Insurance Category

Overweight and Obesity Obesity
MEPS (1998) NHA (1998) MEPS (1998) NHA (1998)
Out-of-pocket $7.1 $12.8 $3.8 $6.9
Private $19.8 $28.1 $9.5 $16.1
Medicaid $3.7 $14.1 $2.7 $10.7
Medicare $20.9 $23.5 $10.8 $13.8
Total $51.5 $78.5 $26.8 $47.5

Framingham Study

  • Obesity is a serious and growing health problem. In 1990, about 56% of adult Americans were overweight and about 23% were obese. By 2000, 64% were overweight and 31% were obese. Overweight and obese people are more likely than normal-weight people to have chronic health problems such as diabetes, high blood pressure, and knee arthritis. They also die at younger ages.

    Although Americans of all ages are increasingly overweight, many find that middle age is a particularly high-risk period for gaining weight. They may not realize that being overweight or obese by middle age is associated with shorter life expectancy. Furthermore, how much shorter life expectancy is among overweight and obese people compared to those of normal weight has not been clear.


Weight Loss Diets

  • Links and basic synopsis