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. 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. What we know so far can be summed up, more or less, as this: Whole-food diets heavy on the fruits, vegetables, and unprocessed protein can lift our moods and protect us from depression, while too much junk food and sugar may put our mental health at risk. One-third of adults in America eat fast food on a given day. Many of us see French fries and chocolate cake as treats to cheer us up when we're feeling down. But perhaps our perspective on food needs an update. With a few simple dietary changes, you might be able to improve both your mind and your mood.