What is intermittent fasting, and is it healthy?

When you hear the word "fasting," you probably think of gimmicky diets—and, um, feeling "hangry." But a growing body of research suggests that cycling super low-calorie days into your normal eating plan could potentially improve your health (more on that later). But before you skip lunch and let your gut start growling, read on for everything you need to know about intermittent fasting.