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:
- Dyslipidemia (for example, high total cholesterol or high
levels of triglycerides)
- Type 2 diabetes
- Coronary heart disease
- Gallbladder disease
- 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
- An adult who has a BMI of 30 or higher is considered obese.
See the following table for an example.
|| 124 lbs or less
|| Below 18.5
| 125 lbs to 168 lbs
|| 18.5 to 24.9
|| Healthy weight
| 169 lbs to 202 lbs
|| 25.0 to 29.9
| 203 lbs or more
|| 30 or higher
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
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
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
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
Table 1, Aggregate Medical Spending, in Billions of
Dollars, Attributable to Overweight and Obesity, by Insurance Status
and Data Source, 1996–1998
| Overweight and Obesity
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.