How to change your metabolism: partial fast two days a week

England Develops a Voracious Appetite for a New Diet
By JENNIFER CONLIN
New York Times
March 1, 2013

PHOTO: Dr. Michael Mosley, a co-author of “The Fast Diet,” cooking a frittata of mushrooms and scallions at home last week. He researched the science of the diet and its health benefits by putting himself through a regimen of intermittent

LONDON — Visitors to England right now, be warned. The big topic on people’s minds — from cabdrivers to corporate executives — is not Kate Middleton’s increasingly visible baby bump (though the craze does involve the size of one’s waistline), but rather a best-selling diet book that has sent the British into a fasting frenzy.

“The Fast Diet,” written by Dr. Mosley and Mimi Spencer, has held the No. 1 slot on Amazon’s British site nearly every day since its publication in January.

“The Fast Diet,” published in mid-January in Britain, could do the same in the United States if Americans eat it up. The United States edition arrived last week.

The book has held the No. 1 slot on Amazon’s British site nearly every day since its publication in January, according to Rebecca Nicolson, a founder of Short Books, the independent publishing company behind the sensation. “It is selling,” she said, “like hot cakes,” which coincidentally are something one can actually eat on this revolutionary diet.

With an alluring cover line that reads, “Lose Weight, Stay Healthy, Live Longer,” the premise of this latest weight-loss regimen — or “slimming” as the British call “dieting” — is intermittent fasting, or what has become known here as the 5:2 diet: five days of eating and drinking whatever you want, dispersed with two days of fasting.

A typical fasting day consists of two meals of roughly 250 to 300 calories each, depending on the person’s sex (500 calories for women, 600 for men). Think two eggs and a slice of ham for breakfast, and a plate of steamed fish and vegetables for dinner.

It is not much sustenance, but the secret to weight loss, according to the book, is that even after just a few hours of fasting, the body begins to turn off the fat-storing mechanisms and turn on the fat-burning systems...