The prevalence of overweight and obesity in the United States

has increased dramatically over the past 3 decades (Ogden et al.,

2002; Flegal et al., 2002). In 1999-2000, 65 percent of adults and

15-16 percent of children ages 6-19 were overweight (NCHS,

2003). Overweight children often become overweight adults, and

overweight in adulthood increases the risk of developing many

diseases, including type 2 diabetes, high blood pressure, coronary heart disease, stroke, gallbladder disease, respiratory problems, osteoarthritis, sleep apnea, and some types of cancer

(Ogden et al.).

Adults have traditionally been classified as overweight based on

life insurance mortality data and data relating weight status to

morbidity and mortality. For adults, a body mass index (BMI),

which is a ratio of body weight (in kilograms) to height squared

(in meters), is used to define body weight status. A BMI of less

than 18.5 is classified as underweight, a BMI at or greater than

18.5 and less than 25 is healthy weight, overweight has a BMI at

or greater than 25 and less than 30, and a BMI at or over 30 is

obese. The Centers for Disease Control and Prevention (CDC)

has issued a series of growth charts for assessing children’s body

weight, including the BMI-for-age chart (ages 2 and over), the

weight-for-length chart (birth through 3 years), and the weightfor-height chart (2-5 years). A child with a BMI-for-age or weightfor-height below the 5th percentile is classified as underweight, at

and above the 85th percentile and less than the 95th percentile is

classified as at risk of being overweight, and at or above the 95th

percentile is classified as overweight. The word “obesity” is not

used with children because of negative connotations. 

The Nutrition and Health Characteristics of Low-Income

Populations study examined several measures of body weight

status for children and adults using 1988-94 National Health and

Nutrition Examination Survey (NHANES) data. The measures

provide a baseline to monitor the weight status of Americans,

focusing on the low-income population. 

Food Stamp Program (FSP) Participants

The FSP income eligibility cutoff (130 percent poverty level)

separates nonparticipants into income-eligible and higher income

nonparticipants. Among children ages 2-19, FSP participants and

income-eligible nonparticipants did not differ in terms of mean

BMI or the proportion of children at risk of being overweight or

who actually were overweight. Compared with higher income

children, however, FSP children were heavier (19.8 vs. 19.2 in

BMI) and were more likely to be overweight (12 percent vs. 9

percent). These differences were concentrated among 12- to 19-

year-old females. FSP females of this age group were heavier

than their higher income counterparts (23.7 vs. 21.8 in BMI) and

were almost twice as likely to be at risk of being overweight or

actually overweight.

Adult FSP participants had a greater mean BMI than either

income-eligible or higher income nonparticipants, and the differences were entirely attributable to differences among women. With

a larger BMI, FSP women were less likely than income-eligible

and higher income women to be at a healthy weight and more

likely to be obese (fig. 1). No difference was observed for the

prevalence of overweight among these three groups of women.

The pattern observed for men is notably different. FSP men and

income-eligible nonparticipating men did not differ in BMI.

Compared with higher income men, however, FSP men were more

likely to be at a healthy weight and less likely to be overweight.

NHANES adult respondents were asked “Do you consider yourself now to be overweight, underweight, or about the right

weight?” More than three-quarters (77 percent) of adults who

were overweight/obese had an accurate perception of their

weight status, with a larger proportion of women (89 percent)

than men (66 percent) being able to recognize their weight problem. A smaller proportion of overweight/obese FSP women recognized their weight problem than income-eligible and higher

income women did (79 percent vs. 85 percent and 92 percent).

No such differences were observed among men. Overall, 25 percent of adults with healthy weight perceived themselves to be

overweight. Healthy-weight men were less likely to perceive

United States

Department of

Agriculture

Economic 

Research

Service

Agriculture Information Bulletin 796-3 February 2005

Nutrition and Health Characteristics of

Low-Income Populations

Body Weight Status

Biing-Hwan Lin, (202) 694-5458, blin@ers.usda.gov
themselves to be overweight than healthy-weight women (11

percent vs. 38 percent). FSP participants who were at a healthy

weight were less likely than higher income nonparticipants to

perceive themselves as overweight (14 percent vs. 27 percent).

This pattern was observed for both men and women. 

Special Supplemental Nutrition Program for

Women, Infants, and Children (WIC)

The WIC program serves infants and children under the age of 5.

Because BMI-for-age is not applicable to children ages 2 and

under, weight-for-height is used to assess the weight status of

WIC children against nonparticipants. The WIC program also

serves pregnant, postpartum, and breastfeeding women, but

weight status for these women is not examined because of data

limitations and lack of appropriate weight cutoffs. The WIC

income cutoff of 185 percent poverty level is used to separate

nonparticipants into income-eligible and higher income groups.

Overweight and underweight are two recognized nutrition risk

criteria for qualifying children for WIC participation.

Among 1- to 4-year-old children, there was no difference

between the three groups in the prevalence of at risk of being

overweight (11 percent, overall). Also, no difference was

observed between WIC children and income-eligible children in

the prevalence of overweight (7-8 percent). However, WIC children were more likely to be overweight than higher income children (7 percent vs. 4 percent). WIC children were more likely

than income-eligible children to be underweight (7 percent vs. 3

percent). There was no difference between WIC children and

higher income children in the prevalence of underweight.

School-Age Children 

Children ages 5-18 who were in school during the survey period

were included in this study. They are grouped into three income

classes: the lowest income (family income not exceeding 130

percent poverty level), low income (131-185 percent poverty),

and higher income (above 185 percent). These income cutoffs

correspond to income eligibility to participate in FSP, WIC, and

free and reduced-price school meals.

On average, children in the lowest income group had a greater

BMI than children in either of the other income groups (fig. 2).

The difference is concentrated among girls, with the lowest

income girls having a mean BMI of 20.4, higher than 19.6 and

19.4 for the low- and higher income girls. Differences between

girls in the lowest income group and the higher income group

are attributable to differences among 11- to 13-year-olds (21.4

vs.19.8) and 14- to 18-year-olds (23.8 vs. 21.7).

Overall, there are no differences between the three income

groups in the prevalence of at risk of being overweight, for either

boys or girls ages 5-18. (Note that 2- to 19-year-old children

who participated in the Food Stamp Program were found to be

heavier than their higher income counterparts, mainly because of

the differences among 12- to 19-year-old females.) There are

some variations in weight status among school-age children by

age. Among the youngest cohort of school-age children (5- to

2 Economic Research Service / USDA

Agriculture Information Bulletin 796-3

Percent of adult males

Food Stamp Program male participants are 

more likely to be obese than other men

Percent of adult females

Figure 1 

Food Stamp Program female participants are 

more likely to be obese than other women

FSP

participants

Income-eligible

nonparticipants

Higher income

nonparticipants

*Statistically significant difference from FSP participants at the 0.05 level or better.

Source: National Health and Nutrition Examination Survey, 1988-94.

Underweight Healthy weight Overweight Obese

FSP

participants

Income-eligible

nonparticipants

Higher income

nonparticipants

25

29

44

20

35

43

20

42*

37*

2 21

42 30*

29

36*

22*

25

49*

26

28

344
10-year-olds), children in the lowest income group were more

likely than children in the low-income group to be at risk of

being overweight (13 percent vs. 8 percent). Among 11- to 13-

year-olds, the lowest income children were more likely than

higher income children to be at risk of being overweight (22 percent vs. 13 percent). This difference is concentrated among girls

(22 percent vs. 12 percent).

Children in the lowest income group were more likely to be

overweight than children in the low- and higher income groups

(fig. 3). There are notable differences by gender. The only difference among boys is observed between the lowest income and

higher income groups, whereas girls in the lowest income group

were almost twice as likely as girls in the low-income group to

be overweight. 

Older Americans

Adults ages 60 and older were classified into three income classes,

identical to the income classification for school-age children. On

average, older adults had a mean BMI of 26.7, above the overweight cutoff. Men and women had similar BMI, and their BMI

tended to decrease with age. Consequently, the proportion of older

Americans with healthy body weights increased and the prevalence of overweight and obesity in general decreased with age.

Older adults in the lowest income and low-income groups were

similar in their BMI, for both men and women. However, older

adults in the lowest income group were heavier than their counterparts in the higher income group (27.3 vs. 26.5 in BMI). This

was caused by differences among females between the two

income groups (27.7 vs. 26.3). Consequently, older females in

the lowest income group were more likely than older females in

the higher income group to be obese (fig. 4). Thirty percent of

older females in the lowest income group were obese, compared

with 21 percent of older females in the higher income group.

Only 30 percent of older females in the lowest income group

were at a healthy weight, compared with 42 percent of older

females in the higher income group. Rates of overweight and

underweight were comparable for the two groups. A different

pattern was noted for men. Specifically, older men in the lowest

income group were less likely than older men in the higher income

group to be overweight and more likely to be underweight (fig. 5).

The data reveal that about two out of three (65 percent) overweight/obese older adults had an accurate perception of their

Economic Research Service / USDA 3

Agriculture Information Bulletin 796-3

Lowest income Low income Higher income

*Statistically significant difference from lowest income group at the 

0.05 level or better.

Source: National Health and Nutrition Examination Survey, 1988-94.

20.2

20.4

20.0

19.6* 19.6* 19.5* 19.5 19.4* 19.5

Overall Males Females

Mean BMI

Figure 2

Mean BMI among school-age children, age adjusted

Lowest income Low income Higher income

*Statistically significant difference from lowest income group at the 

0.05 level or better.

Source: National Health and Nutrition Examination Survey, 1988-94.

14 14

13

10* 10

9* 9*

7*

13

Percent of children

Figure 3

Prevalence of overweight among school-age children, 

ages 5-18, age adjusted

Overall Males Females

Percent of older women

Figure 4

Weight status of older women, age 60 and older, age

adjusted

Underweight Healthy weight Overweight Obese

Lowest

income

Low

income

Higher

income

*Statistically significant difference from lowest income group at the 

0.05 level or better.

Source: National Health and Nutrition Examination Survey, 1988-94.

30 31

35 33

33

42*

34

21*

5 33

30
weight problem, and the accuracy decreased with age. Overall,

77 percent of overweight/obese adults between 60 and 64 perceived themselves to be overweight, compared with 40 percent

of overweight/obese adults 85 years and older. Among overweight/obese older adults, a larger proportion of women (73 percent) recognized their weight problem than men (53 percent).

Overweight/obese women in the lowest income group were less

likely than their counterparts in the other two income groups to

have an accurate perception of their body weight. Among

healthy weight older adults, individuals in the lowest income

group were more likely than individuals in the higher income

group to have an accurate perception of their body weight. That

is, healthy weight older adults in the lowest income group were

less likely than healthy weight older adults in the higher income

group to perceive themselves as being overweight. 

Information Sources

Flegal K.M., M.D. Carroll, C.L. Ogden, and C.L. Johnson.

(2002). “Prevalence and trends in obesity among U.S. adults,

1999-2000.” J. American Medical Assoc. 288:1723-27.

Ogden C.L., K.M. Flegal, M.D. Carroll, C.L. Johnson (2002).

“Prevalence and trends in overweight among U.S. children and

adolescents, 1999-2000.” J. American Medical Assoc. 288:1728-32.

National Center for Health Statistics (NCHS) (2003). Health,

United States, 2003 with Chartbook on Trends in the Health of

Americans. Hyattsville, MD. 

Centers for Disease Control and Prevention (2003). “CDC

Growth Chart Training Modules.” Accessed May 2003, from:

www.cdc.gov/nccdphp/dnpa.

Troiano, R.P., and K.M. Flegal (1998). “Overweight children and

adolescents: Description, epidemiology, and demographics,”

Pediatrics 101:497-504.

4 Economic Research Service / USDA

Agriculture Information Bulletin 796-3

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex,

religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET

Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue,

SW, Washington, DC 20250-9410, or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.

Underweight Healthy weight Overweight Obese

Lowest

income

 Low

income

Higher

income

*Statistically significant difference from lowest income group at the 

0.05 level or better.

Source: National Health and Nutrition Examination Survey, 1988-94.

Percent of older men

Figure 5

Weight status of older men, ages 60 and older, age

adjusted

19

46*

4 2* 1*

33

23 22

37

36

38

37

For more information, see www.ers.usda.gov/publications/ 

efan04014-1, 04014-2, 04014-3, 04014-4

NOTE: These studies were not designed to assess program

impacts. Do not interpret any reported differences between 

program participants and nonparticipants as impacts of food

assistance programs.