Facts and Statistics
What is obesity? Who is obese? How does obesity develop over time? How
can it affect individuals and our society? What can be done about it?
obesity look when illustrated with statistics? We will address
these questions in this section of the Obesity Network.
Statistics Related to Overweight and Obesity
Nearly two-thirds of adults in the United States are overweight, and
30.5 percent are obese, according to data from the 1999-2000 National
Health and Nutrition Examination Survey (NHANES). This fact sheet presents
statistics on the prevalence of overweight and obesity in the U.S., as
well as their disease, mortality, and economic costs. To understand these
statistics, it is necessary to know how overweight and obesity are defined
and measured. This fact sheet also explains why statistics from different
sources may not match.
Overweight and obesity are known risk factors for:
- heart disease
- gallbladder disease
- osteoarthritis (degeneration of cartilage and bone of joints)
- sleep apnea and other breathing problems
- some forms of cancer (uterine, breast, colorectal, kidney, and gallbladder)
Obesity is also associated with:
- high blood cholesterol
- complications of pregnancy
- menstrual irregularities
- hirsutism (presence of excess body and facial hair)
- stress incontinence (urine leakage caused by weak pelvic-floor muscles)
- psychological disorders such as depression
- increased surgical risk
What are overweight and obesity?
Overweight refers to an excess of body weight compared to
set standards. The excess weight may come from muscle, bone, fat, and/or
body water. Obesity refers specifically to having an abnormally high
proportion of body fat. A person can be overweight without
being obese, as in the example of a bodybuilder or other athlete who
has a lot of muscle. However, many people who are overweight are also
How are overweight and obesity measured?
A number of methods are used to determine if someone is overweight
or obese. Some are based on the relation between height and weight; others
are based on measurements of body fat. The most commonly used method
today is body mass index (BMI).
BMI can be used to screen for both overweight and obesity
in adults. It is the measurement of choice for many obesity researchers
and other health professionals, as well as the definition used in most
published information on overweight and obesity. BMI is a calculation
based on height and weight, and it is not gender-specific. BMI does not
directly measure percent of body fat, but it is a more accurate indicator
of overweight and obesity than relying on weight alone.
BMI is found by dividing a person’s weight in kilograms by
height in meters squared. The mathematical formula is:
weight (kg) / height squared (m²).
To determine BMI using pounds and inches, multiply your weight
in pounds by 704.5,* then divide the result by your height in inches,
and divide that result by your height in inches a second time. (Or you
can use the BMI calculator at http://www.nhlbisupport.com/bmi/,
or check the chart shown below that has calculated BMI for you.)
* The multiplier 704.5 is used by the National Institutes
of Health. Other organizations may use a slightly different multiplier;
for example, the American Dietetic Association suggests multiplying
by 700. The variation in outcome (a few tenths) is insignificant.
An expert panel convened by the National Heart, Lung, and
Blood Institute (NHLBI) in cooperation with the National Institute of
Diabetes and Digestive and Kidney Diseases (NIDDK), both part of the
National Institutes of Health (NIH) identified overweight as a BMI of
25-29.9 kg/m², and obesity as a BMI of 30 kg/m² or greater. However,
overweight and obesity are not mutually exclusive, since people who are
obese are also overweight. Defining overweight as a BMI of 25 or greater
is consistent with the recommendations of the World Health Organization
 and most other countries.
Calculating BMI is simple, quick, and inexpensive--but it
does have limitations. One problem with using BMI as a measurement tool
is that very muscular people may fall into the "overweight" category
when they are actually healthy and fit. Another problem with using BMI
is that people who have lost muscle mass, such as the elderly, may be
in the "healthy weight" category--according to their BMI--when they actually
have reduced nutritional reserves. BMI, therefore, is useful as a general
guideline to monitor trends in the population, but by itself is not diagnostic
of an individual patient’s health status. Further evaluation of a patient
should be performed to determine his or her weight status and associated
Why do statistics about overweight and obesity differ?
The definitions or measurement characteristics for overweight
and obesity have varied over time, from study to study, and from one
part of the world to another. The varied definitions affect prevalence
statistics and make it difficult to compare data from different studies.
Prevalence refers to the total number of existing cases of a disease
or condition in a given population at a given time. Some overweight-
and obesity-related prevalence rates are presented as crude or unadjusted
estimates, while others are age-adjusted estimates. Unadjusted
prevalence estimates are used to present cross-sectional data for population
groups at a given point or time period. For age-adjusted rates, statistical
procedures are used to remove the effect of age differences in populations
that are being compared over different time periods. Unadjusted estimates
and age-adjusted estimates will yield slightly different values.
Previous studies in the United States have used the 1959
or the 1983 Metropolitan Life Insurance tables of desirable weight-for-height
as the reference for overweight. More recently, many Government agencies
and scientific health organizations have estimated overweight using data
from a series of cross-sectional surveys called the National Health Examination
Surveys (NHES) and the National Health and Nutrition Examination Surveys
(NHANES). The National Center for Health Statistics (NCHS) of the Centers
for Disease Control and Prevention (CDC) conducted these surveys. Each
had three cycles: NHES I, II, and III spanned the period from 1960 to
1970, and NHANES I, II, and III were conducted in the 1970’s, 1980’s,
and early 1990’s. Since 1999, NHANES has become a continuous survey.
Many reports in the literature use a statistically derived
definition of overweight from NHANES II (1976-1980). This definition
(based on the gender-specific 85th percentile values of BMI for 20 to
29 year olds) is a BMI greater than or equal to (>) 27.3 for
women and 27.8 for men. NHANES II further defines "severe overweight" (based
on 95th percentile values) as BMI > 31.1 for men and BMI > 32.2
for women. Some studies round these numbers to a whole number, which
affects the statistical prevalence. In 1995, the World Health Organization
recommended a classification for three "grades" of overweight using BMI
cutoff points of 25, 30, and 40. The International Obesity Task Force
suggested an additional cutoff point of 35 and slightly different terminology.
The expert panel convened by NHLBI and NIDDK released a report
in June 1998, that provided definitions for overweight and obesity similar
to those used by the World Health Organization. The panel identified
overweight as a BMI > 25 to less than (<)30, and obesity
as a BMI > 30. These definitions, widely used by the Federal
government and increasingly by the broader medical and scientific communities,
are based on evidence that health risks increase more steeply in individuals
with a BMI > 25.
BMI cutoff points are a guide for definitions of overweight
and obesity and are useful for comparative purposes across populations
and over time; however, the health risks associated with overweight and
obesity are on a continuum and do not necessarily correspond to rigid
cutoff points. For example, an overweight individual with a BMI of 29
does not acquire additional health consequences associated with obesity
simply by crossing the BMI threshold > 30. However, health
risks generally increase with increasing BMI.
Prevalence statistics related to overweight
* The statistics presented here are based
on the following definitions unless otherwise specified: overweight =
BMI> 25 to < 30; obesity = BMI > 30.
Overweight and obesity are found worldwide, and the prevalence
of these conditions in the United States ranks high along with other
developed nations. Approximately 300,000 adult deaths in the United States
each year are attributable to unhealthy dietary habits and physical inactivity
or sedentary behavior. 
Below are some frequently asked questions and answers about
overweight and obesity statistics. Data are based on NHANES 1999-2000.
Unless otherwise specified, the figures given represent age-adjusted
estimates. Population numbers are based on the U.S. Census Bureau Census
Q: How many adults are overweight?
A: Nearly two-thirds of U.S. adults are
overweight (BMI > 25, which includes those who are obese).
All adults (20+ years old): 129.6 million (64.5 percent)
Women (20+ years old): 64.5 million (61.9 percent)
Men (20+ years old): 65.1 million (67.2 percent)
Q: How many adults are obese?
A: Nearly one-third of U.S. adults are obese
(BMI > 30).
All adults (20+ years old): 61.3 million (30.5 percent)
Women (20+ years old): 34.7 million (33.4 percent)
Men (20+ years old): 26.6 million (27.5 percent)
Q: How many adults are at a healthy weight?
A: Less than half of U.S. adults have a
healthy weight (BMI > 18.5 to < 25).
All adults (20-74 years old): 67.3 million (33.5 percent)
Women (20-74 years old): 36.7 million (35.3 percent)
Men (20-74 years old): 30.6 million (31.8 percent)
Q: How has the prevalence of overweight and obesity in adults
changed over the years?
A: The prevalence has steadily increased
over the years among both genders, all ages, all racial/ethnic groups,
all educational levels, and all smoking levels.10 From 1960 to 2000,
the prevalence of overweight (BMI > 25 to < 30) increased
from 31.5 to 33.6 percent in U.S. adults aged 20 to 74. The prevalence
of obesity (BMI > 30) during this same time period more than
doubled from 13.3 to 30.9 percent, with most of this rise occurring in
the past 20 years.8 From 1988 to 2000, the prevalence of extreme obesity
(BMI > 40) increased from 2.9 to 4.7 percent, up from 0.8 percent
in 1960.3,8 In 1991, four states had obesity rates of 15 percent or higher,
and none had obesity rates above 16 percent. By 2000, every state except
Colorado had obesity rates of 15 percent or more, and 22 states had obesity
rates of 20 percent or more.11 The prevalence of overweight and obesity
generally increases with advancing age, then starts to decline among
people over 60.
Q: What is the prevalence of overweight and obesity in minorities?
A: The age-adjusted prevalence of combined
overweight and obesity (BMI > 25) in racial/ethnic minorities--especially
minority women--is generally higher than in whites in the United States.
Non-Hispanic Black women: 77.3%
Mexican American women: 71.9%
Non-Hispanic White women: 57.3%
Non-Hispanic Black men: 60.7%
Mexican American men: 74.7%
Non-Hispanic White men: 67.4%
(Statistics are for populations 20+ years old)
Studies using this definition of overweight and obesity provide
ethnicity-specific data only for these three racial-ethnic groups. Studies
using definitions of overweight and obesity from NHANES II have reported
a high prevalence of overweight and obesity among Hispanics and American
Indians. The prevalence of overweight (BMI > 25) and obesity
(BMI > 30) in Asian Americans is lower than in the population
as a whole.
Figure 1. Age-adjusted prevalence of overweight (BMI 25-29.9)
and obesity (BMI > 30)
Source: CDC/NCHS, Health, United States, 2000
* Overweight is defined by the sex- and age-specific 95th percentile
cutoff points of the revised NCHS/CDC growth charts. The revised growth
charts incorporate smoothed BMI percentiles and are based on data from
NHES II (1963-65) and III (1966-1970), and NHANES I (1971-1974), II
(1976-1980), and III (1988-1994); the CDC BMI growth charts specifically
excluded NHANES III data for children ages > 6 years.
Q: What is the prevalence of overweight and obesity in
children and adolescents?
A: While there is no generally accepted
definition for obesity as distinct from overweight in
children and adolescents, the prevalence of overweight* is increasing
for children and adolescents in the United States. Approximately 15.3
percent of children (ages 6-11) and 15.5 percent of adolescents (ages
12-19) were overweight in 2000. An additional 15 percent of children
and 14.9 percent of adolescents were at risk for overweight (BMI for
age between the 85th and 95th percentile).
Q: What is the prevalence of diabetes in people who are
overweight or obese?
A: Among people diagnosed with type 2
(noninsulin-dependent) diabetes, 67 percent have a BMI > 27
and 46 percent have a BMI > 30. About 17 million people
in the U.S. have type 2 diabetes, accounting for more than 90 percent
of diabetes cases. An additional 20 million have impaired glucose
tolerance, sometimes called pre-diabetes, which is a strong risk factor
for developing diabetes later in life. An estimated 70 percent of diabetes
risk in the U.S. can be attributed to excess weight. For more statistics
on diabetes, go to: www.diabetes.niddk.nih.gov/dm/pubs/statistics/index.htm.
Q: What is the prevalence of hypertension (high blood
pressure) in people who are overweight or obese?
A: The age-adjusted prevalence of hypertension
in overweight U.S. adults is 22.1 percent for men with BMI > 25 and < 27;
27.0 percent for men with BMI > 27 and < 30; 27.7 percent
for women with BMI > 25 and < 27; and 32.7 percent for
women BMI > 27 and < 30. In comparison, the prevalence
of hypertension in adults who are not overweight (BMI <25) is 14.9
percent for men and 15.2 percent for women. The prevalence in adults
who are obese (BMI > 30) is 41.9 percent for men and 37.8
percent for women.17 (Hypertension is defined as mean systolic blood
pressure > 140 mm Hg, mean diastolic > 90 mm Hg,
or currently taking antihypertensive medication.)
Q: What is the prevalence of high blood cholesterol in
people who are overweight or obese?
A: The age-adjusted prevalence of high
blood cholesterol (> 240 mg/dL) in overweight U.S. adults
is 19.1 percent for men with BMI > 25 and < 27; 21.6 percent
for men with BMI > 27 and < 30; 30.5 percent for women
with BMI > 25 and < 27; and 29.6 percent for women BMI > 27
and < 30. In comparison, the prevalence of high cholesterol in adults
who are not overweight (BMI <25) is 13.0 percent for men and 13.4
percent for women. The prevalence for adults who are obese (BMI > 30)
is 22.0 percent for men and 27.0 percent for women.
Q: What is the prevalence of cancer in people who are
overweight or obese?
A: While direct prevalence information
is not available, a recent study found that people whose BMI was 40
or more had death rates from cancer that were 52 percent higher for
men and 62 percent higher for women than rates for normal-weight men
and women. Overweight and obesity could account for 14 percent of cancer
deaths among men and 20 percent among women in the U.S. In both men
and women, higher BMI is associated with higher death rates from cancers
of the esophagus, colon and rectum, liver, gallbladder, pancreas, and
kidney. The same trend applies to cancers of the stomach and prostate
in men and cancers of the breast, uterus, cervix, and ovaries in women.
Almost half of post-menopausal women diagnosed with breast cancer have
a BMI > 29.19 In one study (the Nurses' Health Study), women
gaining more than 20 pounds from age 18 to midlife doubled their risk
of breast cancer, compared to women whose weight remained stable.
Q: What is the mortality rate associated with obesity?
A: Most studies show an increase in mortality
rate associated with obesity (BMI > 30). Obese individuals
have a 50 to 100 percent increased risk of death from all causes, compared
with normal-weight individuals (BMI 20-25). Most of the increased risk
is due to cardiovascular causes. Life expectancy of a moderately
obese person could be shortened by 2 to 5 years. White men between
20 and 30 years old with a BMI > 45 could shorten their life
expectancy by 13 years; white women in the same category could lose
up to 8 years of life. Young African American men with a BMI > 45
could lose up to 20 years of life; African American women, up to 5.
Economic costs related to overweight and obesity
As the prevalence of overweight and obesity has increased
in the United States, so have related health care costs--both direct
and indirect. Direct health care costs refer to preventive, diagnostic,
and treatment services (for example, physician visits, medications,
and hospital and nursing home care). Indirect costs are the value of
wages lost by people unable to work because of illness or disability,
as well as the value of future earnings lost by premature death.
Most of the statistics presented below represent the economic
cost of overweight and obesity in the United States in 1995, updated
to 2001 dollars. Unless otherwise noted, the statistics given are
adapted from Wolf and Colditz,24 who based their data on existing epidemiological
studies that defined overweight and obesity as a BMI > 29. Because
the prevalence of overweight and obesity has increased since 1995,
the costs today are higher than the figures given here.
* A recent study estimated annual medical spending due to overweight
and obesity (BMI > 25) to be as much as $92.6 billion in
2002 dollars (9.1 percent of U.S. health expenditures).
Q: What is the cost of overweight and obesity?
A: Total cost: $117 billion
, Direct cost: $61 billion,* Indirect cost: $56
billion (comparable to the economic costs of cigarette smoking)
Q: What is the cost of heart disease related to overweight
A: Direct cost: $8.8
billion (17 percent of the total direct cost of heart disease, independent
Q: What is the cost of type 2 diabetes related to overweight
A: Total cost: $98 billion
Q: What is the cost of osteoarthritis related to overweight
A: Total cost: $21.2 billion, Direct
cost: $5.3 billion, Indirect cost: $15.9
Q: What is the cost of hypertension (high blood pressure)
related to overweight and obesity?
A: Direct cost: $4.1 billion (17 percent
of the total cost of hypertension)
Q: What is the cost of gallbladder disease related to
overweight and obesity?
A: Total cost: $3.4 billion, Direct cost: $3.2
billion, Indirect cost: $187 million
Q: What is the cost of cancer related to overweight and
A: Breast cancer: Total cost: $2.9 billion, Direct
cost: $1.1 billion, Indirect cost: $1.8 billion
Endometrial cancer: Total cost: $933 million, Direct
cost: $310 million, Indirect cost: $623 million
Colon cancer: Total cost: $3.5 billion, Direct cost:
$1.3 billion, Indirect cost: $2.2 billion
Q: What is the cost of lost productivity related to obesity?
A: The cost of lost productivity related
to obesity (BMI > 30) among Americans ages 17-64 is $3.9
billion. This value considers the following annual numbers (for 1994):
Workdays lost related to obesity: 39.3 million
Physician office visits related to obesity: 62.7 million
Restricted activity days related to obesity: 239.0 million
Bed-days related to obesity: 89.5 million
Other statistics related to overweight and obesity
Q: How much do we spend on weight-loss products and services?
A: Americans spend $33 billion annually
on weight-loss products and services. (This figure represents consumer
dollars spent in the early 1990’s on all efforts at weight loss or
weight maintenance including low-calorie foods, artificially sweetened
products such as diet sodas, and memberships to commercial weight-loss
Q: How physically active is the U.S. population?
A: Less than one-third (31.8 percent)
of U.S. adults get regular leisure-time physical activity (defined
as light or moderate activity five times or more per week for 30 minutes
or more each time and/or vigorous activity three times or more per
week for 20 minutes or more each time). About 10 percent of adults
do no physical activity at all in their leisure time.
About 25 percent of young people (ages 12-21 years) participate
in light to moderate activity (e.g., walking, bicycling) nearly every
day. About 50 percent regularly engage in vigorous physical activity.
Approximately 25 percent report no vigorous physical activity, and
14 percent report no recent vigorous or light to moderate physical
Q: What is the cost of lack of physical activity?
A: The direct cost of physical inactivity
may be as high as $24.3 billion.
Q: What are the benefits of physical activity?
A: In addition to helping to control weight,
physical activity decreases the risk of dying from coronary heart disease
and reduces the risk of developing diabetes, hypertension, and colon
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See Also: Defining Overweight and Obesity