In 2002, four Danish scientists began examining grocery receipts. This may sound like a waste of taxpayer dollars, but in fact it was the kind of experiment other scientists describe as “elegant.” For years, science had been grappling with the unexplained health benefits of wine—wine drinkers seemed more resistant to coronary heart disease and certain cancers, but no one knew why. Predictably, there was a large-scale effort to rip wine apart in search of whatever compound was working its peculiar magic on the human body and turn it into a pill. (Resveratrol was one.) The Danish group came at it from a different angle. They didn’t need a gas chromatograph. They needed receipts. They wanted to know what else all those healthy wine drinkers were buying when they visited the supermarket.

Altogether, they examined 3.5 million transactions from 98 supermarkets. They found that wine drinkers didn’t shop the same way as beer drinkers. Wine drinkers were more likely to place olives, low-fat cheese, fruits and vegetables, low-fat meat, spices, and tea in their carts. Beer drinkers, on the other hand, were more likely to reach for the chips, ketchup, margarine, sugar, ready-cooked meals, and soft drinks.

Perhaps the health of wine drinkers isn’t caused by wine so much as by the fact that wine drinkers like wine in the first place. The greatest predictor of health, these results suggest, doesn’t come down to this or that nutrient. It comes down to what a person finds delicious.

— Adapted from The Dorito Effect: The Surprising New Truth About Food and Flavor, by Mark Schatzker (published by Simon & Schuster in May)