The world's most famous yo-yo dieter, Oprah Winfrey, regained the weight once again and trumpeted the fact on the cover of her magazine. Researchers at UCLA reviewed 31 diet studies and found that, within five years, most people regain the weight. Even Weight Watchers distanced itself from the dreaded D-word with its "Diets Don't Work; Weight Watchers Does" campaign.

So why, we wondered, is the renowned Mayo Clinic weighing in with a new diet book, the first in its 120-year history?

We talked to co-author Donald Hensrud, chairman of the clinic's division of preventive and occupational medicine.

Q: It's my understanding that, if you look at medical studies, within four or five years most dieters regain the weight.

A: In general, that's been true for a long time. And if you look at any program that has follow-up out to that length of time, that's generally true. However, a couple of other questions need to be asked: Do we give up? Do we not offer people anything at all? I don't think that's a good option.

Secondly, there are success stories. The National Weight Control Registry was established years ago, and to get into this registry you have to lose 30 pounds and keep it off for a year. They published an article some years ago, where they looked at the experience of people, and the average weight loss was 65 pounds, and people had kept it off for an average of five years. So it is possible, and some people do it.

Q: What makes your diet different?

A: The Mayo Clinic Diet is divided into two phases: The "Lose It!" phase, which is a jump-start phase, where people change habits suddenly, and the "Live It!" phase, which takes those habits that they changed and transitions them into a permanent lifestyle change. The "Lose It!" phase, which is two weeks, is based on adding five habits, breaking five habits and adopting five bonus habits. The philosophy here is that people want to lose weight, they want to see results right away, but many of the methods to do that are either not healthy or not sustainable.

What we did in this phase is we took all the things that have some evidence supporting them — either to decrease calorie intake, increase energy expenditure, or manage weight — and that are healthy, and (we) put them in this. So the composite effect of making all these changes at once is that it's effective, and we believe it's the healthiest way to lose weight quickly there is.

Q: Do you have a favorite change?

A: The first one, eat a healthy breakfast. It sounds very simple. But if you look at the medical literature, there are numerous studies that show that people who eat breakfast, in general, are more successful at managing their weight.

One of the most challenging ones is no TV while eating, and you can only watch as much TV as the time you spend exercising.

Q: I saw that. That one hurt.

A: It does for many people! But it's only for two weeks. It decreases a sedentary activity. It doesn't necessarily have to, but it may promote increased activity or exercise.

Some of the things we've heard from people were, "I didn't realize I was capable of doing this." You know, it does take people out of their comfort zone, and it goes against the (clinic's) traditional doctrine: Slow and steady to start out with, and you're more likely to achieve (your goals) in the long term. But it also makes people aware of their habits suddenly and how much they're capable of changing.