Researchers at Vanderbilt University recruited dieters who typically missed breakfast, and put all women on a 1,2000 calories-a-day diet. One group divided calories between lunch and dinner. The second group at those two meals plus breakfast. Twelve weeks later, the breakfast eaters had lost 17 pounds; the women who didn't eat breakfast had shed 13.

"Wait a minute," you might say. "Weren't both groups consuming the same number of calories?" Only in theory, the researchers concluded. The women who ate breakfast were better able to stick to the 1,200-calorie diet, while those who went hungry until lunch were more tempted to cheat a little.

If you pass up breakfast, this study shows, you're likely to eat more, not less, than if you start the day with a meal. The longer you go without eating, the hungrier you'll get. And the hungrier you get, the more likely you are to reach for an unhealthy snack. When you greet the day with breakfast, you begin by taming the hungry beast inside and make it easier to keep cravings in check. Hunger is closely related to blood sugar, which is to the human body what gasoline is to a car: its primary source of fuel. Eating a good breakfast makes sure there is plenty of blood sugar in your bloodstream available for your body to convert into energy. When blood sugar dips, your body responds with food cravings—and for many people, those cravings are for sugar, since sweet foods convert quickly into blood sugar. But this wreaks havoc on your body's chemistry, particularly your insulin levels, leading to unhealthy eating. Long story short: You want generally stable blood sugar and insulin levels for both your optimum weight and overall health.

The way to achieve that is to eat small amounts frequently. A healthy breakfast not only sets you up for good eating patterns throughout the rest of the day, but immediately takes care of the lower blood sugar level that you have after a night's sleep.