WE SNACK A LOT more often than we think we do. Over time, even occasional snacking can take a toll on our waistlines.

Luckily, making a few small changes in our daily habits can stop—and even reverse—this diet damage.

Here, we asked Cornell professor Brian Wansink, the author of Mindless Eating: Why We Eat More Than We Think, and president-elect of the Society for Nutrition Education, to offer up five tested ways to break your snacking habits and help get you on your way to a lean, healthy body.