Study: Weight gain, fast-food proximity not correlated

A surprising finding suggests that whether a child lives close to fast-food restaurants or fresh-food markets might not have an impact on weight gain.

A new study conducted by IU-Purdue University Indianapolis researchers disproves the conventional assumption that living in close proximity to fast-food establishments increases a child’s weight while living near fresh-food establishments, such as supermarkets, decreases a child’s weight.

In previous cross-sectional studies, researchers used self-reported weights and heights of children, along with their addresses, to make conclusions about the effects of fast food restaurants on body mass index.

“The information gained from this type of study is not able to imply causation,” said the study’s first author, Robert Sandy, IU professor of economics and assistant executive vice president. “It simply looks at what type of people live near fast-food establishments. These families are usually poor, since fast-food establishments heavily reside near major interstates. It also does not properly take into account that families choose where they live. If a family values exercise, they will pay extra to live near a park. These studies fail to conclude that proximity to fast-food establishments causes an increase in weight.”

The IUPUI study was able to provide scientifically verified insight into variables affecting children’s weight by looking at more than 55,000 Marion County participants from ages 3 to 18 during an 11-year span.

“A naturalistic study, where subjects are studied in their own environment over a period of time, enables us to imply causation,” Sandy said. “We are able to look at the exact effect that the addition of a fast-food restaurant or fresh-food supermarket has on the (body mass index) of children.”

Though the IUPUI study carried out by economists, geographers and urban planners found there was little effect on a child’s weight after the addition of fast-food establishments, it did find a decrease in the weight of children after the addition of recreational amenities. Investigators approximate that the addition of a fitness area such as a baseball diamond can lower the weight of an 8-year-old boy by 3 to 6 pounds.

“Along with the additions of recreational facilities, we also looked at the effects of crime rates on a child’s (body mass index),” Sandy said. “If an area is unsafe, these facilities will not have desired effects, since parents will not allow children to use them. Public policymakers need to look at both crime rates and recreational facilities together.”