Should you eat an apple—or a bag of Oreos? Go to McDonald’s—or the vegetarian restaurant on the corner? When we make these everyday food choices, many of us think first of our physical health and appearance. But there’s another factor we may want to consider in picking foods: their impact on our mental health.

A growing body of research is discovering that food doesn’t just affect our waistline but also our moods, emotions, and even longer-term conditions like depression. Which makes sense, after all.

Our brains are physical entities, running on the energy that we put into our bodies, affected by shifts in our hormones, blood sugar levels, and many other biological processes.Although there are many unanswered questions, the research to date can give us some guidance when we’re hunting for an afternoon snack.