Waiting more than three hours, claims Cruise, causes the body to burn muscle because it believes that it is starving -- metabolism drops and the weight adds up. But Cruise asserts that eating every three hours keeps the body's metabolism at a quick pace, enabling the dieter to eat as they please.
Forget counting the calories and keeping an eye on the carbohydrates - according to America's new fad diet you can eat whatever you want.
US fitness guru Jorge Cruise reckons it's not what you eat, it's simply a matter of timing.
That means taking your meals at three-hour intervals, without snacks.
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He says you can eat whatever you want, with no stinting on the cake, chocolate and ice cream - and even drink alcohol.
Californian Cruise, 34, whose book 3-Hour Diet is a US bestseller, says the time limit allows your body to reset and revive its metabolism.
'By going more than three hours between meals, the body turns on its natural "starvation protection mechanism" and starts to burn muscle,' he added.
'By eating every three hours, your metabolism stays revved and your body burns fat instead of muscle.'
Traditional low-carbohydrate, lowcalorie diets don't work, he says, because they lower your metabolism and make your body burn muscle instead of fat.
'The timing allows you to lose 2lb (1kg) a week, starting with belly fat - but without low-carb dieting.
Brigid McKevith, of the British Nutrition Foundation, said: 'It's an interesting concept but for some people there's the danger of eating far too much, which kind of defeats the object.
Lots of fruit and veg are the key to this, I think.'
The 3-Hour Diet will be published in the UK later this summer.