Olympic swimming champion Michael Phelps has a message: eat like a pregnant woman, and you’ll win Olympic gold.

Breakfast: 3 fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and mayonnaise.He follows that up with two cups of coffee, a five-egg omelet, a bowl of grits, three slices of French toast topped with powdered sugar and three chocolate-chip pancakes.

Lunch: Phelps gobbles up a pound of enriched pasta and two large ham and cheese sandwiches slathered with mayo on white bread - capping off the meal by chugging about 1,000 calories worth of energy drinks.

Dinner: He loads up on the carbs - what he needs to give him plenty of energy for his five-hours-a-day, six-days-a-week regimen - with a pound of pasta and an entire pizza. He washes all that down with another 1,000 calories worth of energy drinks.

The Phelps diet is not recommended for everyone. Due to his muscle-intensive physique, the swimmer's metabolism - the process of converting food into energy - far exceeds that of a more average man, said Jeff Kotterman, director of the US National Association of Sports Nutrition.

"It's a combination of peak performance coupled with the fact that he has an enormous metabolism - he burns more calories sitting at a desk than a lot of people burn walking," Mr Kotterman told the BBC.

He suggested Phelps, with an estimated 8% body fat, probably burns 1,000 calories per hour during his swimming training, compared to the equivalent exercise for an average person - vigorous walking - that would burn between 170 and 240 calories.

Consequently, trying to emulate the Phelps diet by consuming up to 12,000 calories a day in order to attain his physique would more than likely come to a wobbly end.

One pound of fat has roughly 3,500 calories, so an ordinary man could put on almost three pounds of fat a day.

But then again, Michael Phelps - who has now won the 400m medley, 200m freestyle, 200m butterfly, 4x100m free relay, 4x200m free relay and the 200m medley in world record times - is clearly no ordinary man.