One of the most worrisome aspects of the growing tide of obesity in the United States is the high 

rate of overweight among children. Over one in fi ve young children, ages 2 to 5, are at risk of being overweight—meaning their Body-Mass-Index-for-age is at or above the 85th percentile.Th ese 

children face both current and long-term health problems, and their numbers have grown in the past 

two decades (Must and Strauss, 1999). Th e number of young children whose families participate in 

the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) also grew 

in that time period, more than doubling from 1.7 million in 1988 to 4.0 million in 2007 (USDAERS, 2008).

Are these increases connected? Does WIC participation contribute to the problem of overweight 

among U.S. children? Although causes of the increase in childhood overweight and obesity are complex, the answer to both questions appears to be “No.” Results from data covering almost 20 years 

show no association between WIC participation and Body Mass Index (BMI) or the probability of 

being at risk of overweight (see box, “Calculating Body Mass Index,” p. 4). However, low-income 

status, especially for Mexican-American children, does raise the probability of a child’s being at risk 

for overweight.

Th is brief examines trends in the relationship between WIC participation and weight status by 

updating the results of Food and Nutrition Assistance Programs and Obesity: 1976-2002 (ERR-48, 

Ver Ploeg et al., 2007). Th at analysis has been updated to include more recently released data from 

the 2003-2006 National Health and Nutrition Examination Survey (NHANES, 1988-1994 and 

1999-2006). 
ECONOMIC BRIEF WIC and the Battle Against Childhood Overweight

UNITED STATES DEPARTMENT OF AGRICULTURE 2

Background and Methodology

Th e percentage of boys ages 2-5 at or above the 85th percentile of BMI-for-age rose from 15.2 percent to 

22.5 percent between 1988-1994 and 1999-2006 (see fi g. 1). Th e increase for girls was smaller, but still 

sizable, increasing from 16.1 percent to 20.6 percent over the same time period, according to NHANES.

Economic Research Service (ERS) analysts examined the relationship between WIC participation and 

BMI over the past two decades. Data from the National Health and Nutrition Examination Survey 

(NHANES) covering the years from 1988-1994 and 1999-2006 were used to explore whether or not 

there is a relationship between WIC participation and body weight and whether that relationship has been 

consistent over time as the number of children who participate in the WIC program increased. (Th e 1988-

94 NHANES oversampled Mexican Americans, but not other Hispanic Americans. Th e sample size does 

not support separate estimates representative of all Hispanic Americans, only Mexican Americans.)

Th e analysis compared boys and girls separately. Further, the analysis compared children who reported 

receiving WIC benefi ts with children who were income-eligible but did not receive benefi ts (income less 

than or equal to 185 percent of Federal poverty guidelines), with children who had moderate income 

levels (income between 185 and 300 percent of Federal poverty guidelines) and higher income levels 

(income above 300 percent of poverty).1

 Race, ethnicity, and age were also controlled in the analysis. 

Body Weight Is Not Related to WIC Participation

Th e only instance in which WIC participation was associated with the probability of overweight was in 

1988-1994 for girls—showing that WIC participants were less likely to be at risk of overweight than 

moderate-income children. 

Boys—Estimates for both sets of years of data showed that young boys who received WIC benefi ts had 

similar BMI and were as likely to be at risk of overweight as income-eligible nonparticipants. Further, 

there were no signifi cant diff erences between WIC participants and higher income nonparticipants. 

Mexican-American boys had signifi cantly higher BMI than nonHispanic White boys in both 1988-1994 and 1999-2006, even 

after controlling for income, food stamp participation and age 

(fi g. 2). Mexican-American boys were also more likely to be at 

risk of overweight than non-Hispanic White boys in 1988-1994, 

but this diff erence was no longer statistically signifi cant in 1999-

2006. Th ere were no diff erences between BMI and the probability 

of being at risk of overweight between non-Hispanic White and 

non-Hispanic Black boys.

Girls—Girls who received WIC have similar BMI as incomeeligible nonparticipants and as higher income nonparticipants. 

No diff erences in BMI between these groups were found in 

either 1988-1994 or 1999-2006. Similarly, there were no 

diff erences in the probability of being at risk of overweight across 

WIC participation and income level. Th ere was one exception, 

however—1988 to 1994 data show that moderate-income girls 

were more likely to be at risk of overweight than WIC participants. 

Th is diff erence was no longer present in 1999-2006. 

Race and ethnicity were important predictors of BMI and the 

probability of being at risk of overweight among girls as well. 

1

Th e Federal poverty threshold for 

a family of 4 in 2008 was $21,200 

and the 185-percent eligibility 

limit for WIC was $39,220. 

15.2%

1988-1994

Boys

ages 2-5

Girls

ages 2-5

1999-2006

16.1%

22.2%

20.6%

Figure 1

Children with Body-Mass-Index-for-age at or above 

the 85th percentile

Source: ERS estimations using National Health and Nutrition 

Examination Survey data.
WIC and the Battle Against Childhood Overweight ECONOMIC BRIEF

3 ECONOMIC RESEARCH SERVICE

Credit for cover photos:

Group of children, Digital 

Vision; mother and child, 

baby in shopping cart, 

Shutterstock.

Compared with non-Hispanic White girls, MexicanAmerican girls had greater BMI. Th is result is 

consistent for both time periods. In 1988-1994, 

Mexican-American girls were also more likely to be 

at risk of overweight than non-Hispanic White girls. 

Th is diff erence, however, was not signifi cant in the 

more recent period, 1999-2006. Non-Hispanic Black 

girls had similar BMI as non-Hispanic White girls for 

both survey periods. However, in 1999-2006, nonHispanic Black girls were more likely to be at risk of 

overweight than non-Hispanic White girls. 

One area for concern among young children regardless 

of income is that young Mexican-American girls and 

boys had greater BMI than non-Hispanic White 

children and non-Hispanic Black children. Figure 2 

shows diff erences in BMI across race and ethnicity 

for boys in 1999-2006. In 1988-1994, this translated 

into greater likelihood that young Mexican-American 

boys would be at risk of overweight than their nonHispanic White counterparts, but the latest data 

showed no statistically signifi cant diff erences for the 

probability of being at risk of overweight. Another 

potential area of concern was that in 1999-2006, nonHispanic Black girls were more likely to be at risk of 

overweight than non-Hispanic White girls. 

Although these results do not show evidence of a relationship between WIC participation and body 

weight, ERS analysis methods cannot ascribe (or deny) causal links between WIC participation and 

overweight status. Selection bias may exist because families and individuals who choose to participate in 

food assistance programs may be systematically diff erent in unobservable ways from those who do not 

participate. 

Conclusions

Th e WIC program appears not to be a major cause of the childhood obesity problem, but the program 

could be part of the solution. WIC could be used as a tool to combat the problem of overweight among 

children, at least for those low-income children whom the program primarily serves. By October 1, 2009, 

the WIC program must implement recently approved changes to the types and amounts of foods the 

program off ers, including a voucher for the purchase of fruits and vegetables. 

State WIC agencies now are implementing the changes in the types and quantities of foods that can be 

purchased through WIC. Th e new WIC food package for children 2 years and older eliminates whole 

milk and makes available only lower fat milk, reduces the maximum monthly amount of juice and eggs, 

adds whole-wheat bread, and includes a voucher for $6 per month to buy fruits and vegetables. Such 

changes could be important for reducing the risk of obesity if they encourage consumption of more fruits 

and vegetables and lower fat milk while reducing consumption of less healthy foods. 

Th e revisions to the food package also attempt to encourage breastfeeding. Th e changes include:

• making the food package for postpartum women who exclusively breastfeed relatively more 

generous than the food package for partially breastfeeding and nonbreastfeeding postpartum women 

(off ering more juice, milk, eggs, whole-wheat bread, canned fi sh, and off ering a $10 voucher for 

16.0

16.1

1988-1994 1999-2006

16.5

16.3

16.2

16.7

16.8

16.7

16.4

16.2

16.0

15.8

15.6

Non-Hispanic White

Non-Hispanic Black

Mexican American

Mean predicted BMI

Note: Differences among groups and between years are not statistically significant.

Figure 2

Mean BMI by race/ethnicity for boys ages 2-4 who were enrolled 

in WIC, 1988-1994 and 1999-2006

Source: ERS estimations based on regressions of BMI on age, race/ethnicity, WIC, 

and income status.

3
Ver Ploeg, Michele. WIC and 

the Battle Against Childhood 

Overweight. EB-13, U.S. Department of Agriculture, Economic 

Research Service. April 2009. 

Recommended citation 

format for this publication:

References

Arenz, S, R. Rückerl, B. Koletzko, and R. von Kries. 2004. 

“Breast-feeding and Childhood 

Obesity—A Systematic Review,” 

International Journal of Obesity, 

Vol. 28:1247-1256. 

Must, A., R.S. Strauss. 1999. 

“Risks and Consequences of 

Childhood and Adolescent Obesity,” International Journal of Obesity, 

Vol. 23, Suppl. 2, S2-S11. 

National Health and Nutrition 

Examination Survey (NHANES). 

1988-1994 and 1999-2006. U.S. 

Department of Health and Human Services, Centers for Disease 

Control and Prevention, National 

Center for Health Statistics. Available at: http://www.cdc.gov/nchs/

nhanes.htm/.

U.S. Department of Agriculture, 

Economic Research Service. 2008. 

Average Monthly Participation in 

WIC: Fiscal 1980-2006. Available at: http://www.ers.usda.gov/

briefi ng/ FoodNutritionAssistance/

gallery/ wic.htm/. Accessed June 3, 

2008. 

Ver Ploeg, M., L. Mancino, and 

B.H. Lin. 2007. Food and Nutrition Assistance Programs and Obesity: 1976-2002, U.S. Department 

of Agriculture, Economic Research 

Service, ERR-48, September 2007. 

ECONOMIC BRIEF WIC and the Battle Against Childhood Overweight

UNITED STATES DEPARTMENT OF AGRICULTURE 4

fruits and vegetables compared with an $8 voucher for partially breastfeeding and nonbreastfeeding 

women).

• eliminating the provision of infant formula for fully breastfed infants

• reducing the amount of formula provided for partially breastfed infants

If these revisions are successful in promoting breastfeeding, a longer term impact of reducing childhood 

obesity could occur, since breastfeeding may protect babies against becoming obese later in life (Arenz 

et al., 2004). Future research and evaluation should assess the eff ectiveness of these policy innovations 

in changing dietary patterns, as well as others that may be proposed as a way to reduce the prevalence of 

child obesity. 

Body Mass Index (BMI) is a function of weight and height. In English units, it is measured 

as pounds divided by inches squared, multiplied by 703.

Adults

As an example, a 5-foot, 5-inch (65 inches) adult weighing 150 lbs would calculate his 

BMI by: dividing 150 by (65)2 and multiplying the result by 703, for a BMI of 24.96. That 

is just within the high end of the healthy-weight range, as shown below.

BMI < 18.5 = underweight 

18.5 ≤ BMI < 25 = “normal” or healthy weight

25.0 ≤ BMI < 30 = overweight

BMI ≥ 30.0 = obese

Children

For children, the calculation is more complex, involving date of birth (month/day/

year), date of measurement (month/day/year), gender, height (to nearest one-eighth 

of an inch), and weight (to nearest one-quarter of a pound). That number is placed on 

a Centers for Disease Control and Prevention BMI-for-age percentile chart that places 

the child within a BMI range for the child’s peers.

As an example, the BMI calculated for a 7-year-old girl who weighs 55 pounds and is 

48 inches tall would be done the same way as an adult’s BMI. The result, a BMI of 16.8, 

would be placed on the CDC chart, showing she is just above the 75th percentile, 

meaning her BMI is higher than 75 percent of girls her age in the United States.

Children and adolescents ages 2-19

BMI < 5th percentile of BMI-for-age = underweight

5th percentile of BMI-for-age < BMI < 85th percentile BMI-for-age = healthy weight

85th percentile BMI-for-age < BMI < 95th percentile BMI-for-age = at risk of 

 overweight

BMI > 95th percentile of BMI-for-age = overweight

Calculating Body Mass Index

To calculate specific BMIs for adults, children, and teens, see:

http://www.cdc.gov/nccdphp/dnpa/healthyweight/assessing/bmi/index.htm

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