WalMart makes you skinny

Oh man. There is a study coming out of UNC which seems to suggest that people with access to WalMart/Sam's /Costco may actually be skinnier than those who don't shop at such stores.

In this summary, the study (which was assessing links between obesity and discount retail stores) actually showed that access to WalMart was associated with a lower body-mass index and a lower probability of being obese. Further analysis which included other discount retail giants seemed to confirm the effect; interestingly enough, WalMart's positive effect on weight was most pronounced for women, the poor, African-Americans and people who live in urban areas. There was also a positive correlation between better eating habits and the presence of discount club stores.

There are a few explanations given by the study authors. First is the substitution effect, whereby a change in prices relative to one another leads to, for example, cheaper salad prices (as compared to chip prices).

Another suggested explanation is the income effect. "If Wal-Mart sells food at lower prices--even if our incomes don't change--every dollar can buy more. Therefore, we're richer."

Is this a definitive study? Nah--not by a long shot. I kind of think of it as one of those "caffeine studies"--you know, the ones that come out every few weeks that have caffeine intake first associated with heart disease, then lower blood pressure, then increased mental acuity, or a variety of conflicting and seemingly unassociated outcomes.

It is interesting that the "conventional wisdom" would have it that big bad WalMart makes poor people fat and sells "bad food." Why do we believe this? I don't know. It's a commonly held belief. WalMart is often portrayed as the big bad monster destroying local communities and devouring the people that live in them. I do know that I have been surprised by what I am able to buy at the WalMart here in Rockettown. It's not Whole Foods, but it's not hard to find a variety of healthy foods to eat.

You can choose to believe what you want about WalMart. But this study won't exactly back up your prejudices.