"You want to eat a handful of nuts every day," Dr. Roizen says. "Walnuts and almonds are excellent. And you want to eat five handfuls of fruits and vegetables every day. Then you want some whole grains and some whole grain cereal."

"Don't make the mistake of 'whole wheat' being 'whole grain,'" Oprah says. "There is a difference. It should say whole grain."

Dr. Roizen cautions against eating foods like corn too often, because the body absorbs sugar differently. He says it is important to eat some fat, like nuts, before eating sugars. "Having the walnuts or almonds a little bit before you have [sugar] slows your stomach from emptying," Dr. Roizen advises. "One, you feel full and you don't eat as much. And, two, because sugar's absorbed after the stomach, in the intestine, you keep your blood sugar level more constant."