There's a new diet out of England that claims you can eat whatever you want, as much as you want, then fast for the other two days.

That's right.  According to this plan, you can eat pizza and ice cream by the barrels on your eating days, then two days a week you rein it in to practically nothing.  500 calories for women and 600 for men.

The diet comes from a book called "The Fast Diet".  It was published in January in England, and it's been the top bestseller there ever since.  The U.S. version just went on sale.

Dr. Michael Mosely is the author of the book.  He says it's healthy and it works, because switching from heavy eating to fasting immediately takes your body into hardcore fat burning mode.

Mosley tested the diet on himself and lost 20 pounds in nine weeks.  His cholesterol and overall body fat level also went down.  He says that lowers the risk of cancer and heart disease.

Nutritionists are skeptical and warn that this kind of fasting might be unhealthy.

As with any diet or exercise program, you should consult your doctor first.