RAND Office of Media Relations
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October 5, 2005
Young school-age children who live in communities where fruits and vegetables are expensive are more likely to gain excessive amounts of weight than children who live in areas where fruits and vegetables cost less, according to a RAND Corporation study issued today.
The RAND Health study is the first to link the relative cost of fruits and vegetables to excessive weight gain relative to height among young children.
“These findings may help explain the growing obesity epidemic among children over the past 20 years,” said Roland Sturm, a RAND senior economist and lead author of the study. “During the same time period, prices of fruits and vegetables have increased faster than other food prices, and faster than the cost of living.”
The study, published in the medical journal Public Health, found no significant relationship between children's excess weight gain and the presence of many convenience stores, full service restaurants, limited service restaurants (primarily fast food restaurants), or grocery stores near their homes. Advocacy groups have suggested that such a link might exist.
“This is the first study that considers the relationship between children's weight gain and the density of food establishments and the price of food across the nation,” Sturm said.
Sturm and co-author Ashlesha Datar examined the weight gain of 6,918 children from 59 metropolitan areas around the United States over the time the children advanced from kindergarten through third grade. The researchers then compared the weight gain figures with the relative price of fruits and vegetables in each of the areas studied.
On average, children everywhere gained more weight than they should have according to clinical growth charts. From the beginning of kindergarten to the end of third grade, the child at the 50th percentile should gain about 22 pounds according to the growth charts, but actually gained 25.5 pounds. On average, children in the study gained 29 pounds.
But children who lived in metropolitan areas where fruits and vegetables were relatively more expensive gained significantly more weight than similar children living where fruits and vegetables cost less.
For the region with the highest relative price for fruits and vegetables — Mobile, Ala. — children gained about 50 percent more excess weight as measured by body mass index (a ratio of height to weight) than children nationally. Among children in the area with the lowest relative cost for fruits and vegetables — Visalia, Calif. — excess BMI gain was about half the national average.
Researchers ranked the cost of fruits and vegetables for each region by comparing the cost to other common expenses such as housing and transportation. Fruits and vegetables cost about twice as much in the cities with the highest relative prices for these foods compared with cities with the lowest cost for fruits and vegetables, according to the study.
“We don't have data on consumption, so we cannot say whether prices lowered purchases of fruits and vegetables,” Sturm said. “Our findings suggest the need for more research to determine what impact the higher prices may have on the consumption of fruits and vegetables among children.”
The U.S. Department of Agriculture provided support for the RAND research. Previous research by the department concluded that prices nationwide are sufficiently low so that even low-income families can afford recommended amounts of fruits and vegetables. However, low-income families in the United States are twice as likely as higher income families not to buy any fruits or vegetables in a given week.
RAND Health is the nation's largest independent health policy research program, with a broad research portfolio that focuses on health care quality, costs and delivery, among other topics.
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