Living Near Fast Food Outlet Promotes Obesity – Or Not?

Yesterday, a big new item was a study by University of Alberta’s John Spence and colleagues published in BMC Public Health, that reported the increased likelihood of having obesity when living in neighbourhoods with a high Retail Food Environment Index (RFEI), i.e. a high ratio of fast food restaurants and convenience stores compared to grocery stores and produce vendors.

This finding was based on a representative telephone survey of 2900 individuals from the City of
Edmonton, who provided complete height and weight information. Data were adjusted for age, sex, socioeconomic status, employment status and level of education (the latter parameters were extrapolated from postal code information).

The odds of being obese were significantly higher, the greater the ratio of fast-food restaurants and convenience stores to grocery stores and produce vendors near the home. This association existed for establishments within an 800 m buffer around people’s homes but not for establishments within 1600 m of their homes, suggesting that it is indeed the proximity to the fast-food outlet that matters.

Interestingly, also yesterday, another study was in the news: this one, from Indiana University-Purdue University Indianapolis (IUPUI) contradicts the finding that living near a fast food outlet increases weight in children and that living near supermarkets, which sell fresh fruit and vegetables lowers weight.

In this study, the Purdue researchers looked at medical records of 60,000 children between the ages of 3 and 18 who went to an Indianapolis health care facility between 1996 and 2006. The children’s body mass index was tracked over the years, as was the development of neighborhood fast food restaurants, supermarkets and recreational facilities accessible to the public, such as basketball courts, pools and soccer fields.

Fast food restaurants had little discernible effect on weight, as did supermarkets that sell fruits and vegetables. In contrast, living close to a recreational facility marginally lowered the risk or excess weight.

Clearly, given the large number of confounders that can potentially affect the outcomes of such studies, I believe that the ultimate verdict is still out (personally, I tend to go with the Purdue study, given the far larger sample size and longitudinal nature of the study).

Obviously, neighbourhoods with more fast-food restaurants may have other characteristics that promote weigh gain than simply the presence of the fast-food restaurants themselves – or fast-food may have nothing to do with this at all – not a debate that is likely to end anytime soon.

As blogged before, I still think that fast-food outlets are a symptom or a “surrogate measure” of an obesogenic society rather than a direct cause of obesity.

Edmonton, Alberta