Want to lose a few before the upcoming holidays? Fill up with fiber.

It's no news that boosting your fiber intake is good for your health. But boosting it at breakfast may be the key to staying lean, say RealAge doctors Michael Roizen and Mehmet Oz. In their new-this-week book, YOU: On a Diet, they suggest putting fiber-rich foods like oatmeal, whole-grain toast, or a veggie-packed omelet on your morning menu to curb afternoon binging on Cheetos or cookies. That's because fiber acts like a speed bump in your gastrointestinal tract, slowing everything way down, so you stay fuller longer.

This is one way you can use your body chemistry, not willpower, to curb cravings and get to your ideal body size. Learn other science-based strategies like this from Roizen and Oz's YOU: On a Diet plan.

Believe it or not, enjoying a fiberful diet -- especially at breakfast -- can reduce your calorie intake for up to 18 hours a day. And it helps control blood sugar and lower insulin levels. Although you should aim for 25 to 30 grams of fiber a day, avoid adding it all at once or you'll produce more gas than a Saudi oil field, say the doctors. Start with an additional 1 to 2 grams of dietary fiber -- the amount in a slice of whole-grain bread or 1/2 cup of green beans -- at and between meals and slowly increase from there.

YOU: The Owner's Manual. Roizen, M. F., Oz, M. C., New York: HarperCollins 2005.