You are what you eat. It's an expression with roots in the early 1800s that has come to mean if you consume what's good for you, you will be healthy, and if you don't, well, watch out. But our latest research on what influences consumers to make unhealthy food choices has compelled us to turn that axiom on its head: You eat what you are.

As a predictor of unhealthy food consumption, social and demographic factors were nearly twice as important as where a person shopped for food, according to our recent RAND study. The findings come from an ongoing project studying food consumption and food shopping of residents in two low-income Pittsburgh neighborhoods that have long been considered food deserts.

As researchers trying to figure out ways to help people eat better, what we found caused us to think twice about focusing too much on providing more access to healthy choices. We needed to grapple with a version of the nature versus nurture debate that had arrived in the supermarket aisle ...

Young consumers were less likely to eat fruits and vegetables, which should come as no surprise to parents everywhere. People without college degrees consumed significantly more sugar-sweetened beverages and "discretionary fats," such as butter. With age and education came better eating habits. Older people and college graduates ate more fruits and vegetables.

The clear role played by these sociodemographic connections argues for proactive approaches to help people improve the dietary choices they make. Particularly when it comes to eating less junk food, targeted interventions are needed in addition to building supermarkets and stocking them with “good for you” foods.

Read the full article about addressing America's food deserts by Christine Anne Vaughan and Tamara Dubowitz at RAND Corporation.