The Biology of Blubber

Stepping on a scale is the primary way that people measure the success of their diet, Dr. Oz says, "because it's easy to do. But it's actually misleading in many ways."

For one thing, muscle weighs more than fat. By turning fat to muscle, you'll weigh more even though you'll be healthier. Also, weight doesn't tell you where the fat is. Fat around your legs and thighs is relatively harmless, but fat around your waist can lead to serious medical problems.

Instead of focusing on the number on the scale, Dr. Oz says to focus on the number around your waist. The ideal waistline for women is 32 and a half inches and 35 inches for a man—a goal that is achievable by everyone, no matter your age, Dr. Oz says. In the Oprah Show audience 47 percent of women and 93 percent of men were over the ideal waist size.

"Mike and I are doctors," Dr. Oz says. "I want you guys to look beautiful out there...but I want you to be alive to enjoy it. And that's what this is all about."