IStock Photo 4837929 © Justin Voight

The odds an American will make a New Year’s resolution to eat a healthier diet, either by consuming less or by making smarter choices, are 1 in 4.76. Food choices are critical to our health because what we eat to a large degree determines how well we are. Poor eating habits don’t just promote physical problems like obesity, heart disease, and some types of cancer—they also can affect your mind. One recent British study found a link between diets high in processed foods and depression. In a different US study, 106 overweight subjects went on diets, but half followed a low-fat, high-carbohydrate regimen while the others did the opposite. Both groups lost weight, but the people who ate food high in carbs reported feeling happier and less depressed than they had before starting.

That convergence could account for the highly similar odds that an adult in the US often overeats junk food (1 in 5.26) and that an adult has been diagnosed with a major depressive disorder (1 in 5.92). Americans seem to realize that we often misuse food: the odds that an adult sometimes overeats junk food are 1 in 2.78, and the odds that a person does not consider him- or herself a healthy eater are identical.

There are plenty of scapegoats for our eating habits, including stress, busy schedules, inactivity, and lack of access to healthy foods, especially in low-income areas. These factors contribute to our high consumption of fast foods: the odds that an adult will eat a meal at a fast-food restaurant weekly are 1 in 2.44. Some critics, such as former Food and Drug Administration commissioner David Kessler, argue that foods high in fat, salt, and sugar actually stimulate our brains and make many of us want to overeat.

But if homey dishes like macaroni and cheese don’t make us feel good, why do we call them “comfort foods”? Even globe-trotting celebrity chefs have favorite comfort dishes, whether it’s meatballs, mashed potatoes, or a big bowl of pasta. Typically, these dishes are full-flavored and simple to make, and evoke warm associations with childhood, family, and tradition. And there’s the hook: scientists have found that when people are under psychological stress their bodies produce glucocorticoids, a hormone that triggers the urge to eat pleasurable foods.

Filling up on comfort foods eases our nerves temporarily, but the nutritional impacts are long-lasting. A 2005 ABC poll found that nearly 6 in 10 adults report they turn to fattening food for comfort; among overweight adults the ratio is 2 out of 3. Happily, we can have comfort food without putting on extra pounds. Some classics, like chicken noodle soup, are low in calories. Food and health writers are lightening up others with leaner cuts of meat and fewer sauces. Best of all, dark chocolate really is good for you, mentally as well as physically: it boosts brain levels of endorphins (natural pain-killing substances) and serotonin, a chemical that improves mood and promotes feelings of relaxation.

According to the ABC poll, chocolate tops the list of indulgence foods: 20% of Americans crave it, a higher percentage than those who reach for either ice cream or cake. But chocolate is still high in fat and calories, so keep your fix small—doctors recommend 1 to 1.5 ounces per day—and chase it with an apple.