As US swimming sensation Michael Phelps sets his sights on more gold medal wins at the Beijing Olympics this weekend, the BBC's Michael Hirst examines the part an extraordinary diet has played in the sportsman's remarkable success.

If it is true that you are what you eat, then here is the suggested intake if you want to become history's most successful Olympian:

For breakfast: three fried egg sandwiches, with cheese, tomatoes, lettuce, fried onions and mayonnaise, followed by three chocolate-chip pancakes; a five-egg omelette; three sugar-coated slices of French toast and a bowl of grits (a maize-based porridge), washed down with two cups of coffee.
For lunch: half a kilogram (one pound) of enriched pasta; two large ham and cheese sandwiches on white bread smothered with mayonnaise, washed down by energy drinks.

For dinner: Another half-kilogram of pasta, perhaps with a carbonara sauce, followed by a large pizza and more energy drinks.

That combination may not sound very healthy, and at a staggering 10,000 calories, would feed five average men for a day.

But the menu is reportedly all in a training day's eating for champion swimmer Michael Phelps, who won six gold medals in the 2004 Athens Olympics and is aiming for eight this time round.

"Eat, sleep and swim, that's all I can do," said the US swimmer, after winning his 11th Olympic gold.
Judging by the amount he eats and swims, that is not altogether surprising.

Fruit and veg

Even though the 23-year-old spends a solid five hours of each day burning off those calories, the diet still seems excessive. Is he following some sort of dietician guru's programme?

Barbara Lewin, a nutritionist who has advised international athletes on their dietary health for almost two decades, thinks not.

Health-wise, if he were eating like this long-term, he'd probably be having to see a cardiologist regularly," Mrs Lewin told the BBC.

She recommended cutting out the egg yolks, replacing the white bread with whole-wheat, throwing some fruit and vegetables into the mix, and spreading the food out over the day with regular snacking. But while the quality of the calories consumed by the six-foot four-inch (1.93m) swimmer may not seem healthy, Ms Lewin suggested there are good reasons behind Mr Phelps' diet.

"I've worked with more than 1,000 endurance athletes - swimmers and runners - and one of the most common problems they have is glycogen depletion - the result of not getting enough carbohydrates," she said.

"Nine out of 10 times the reason an athlete doesn't reach their personal best is because they're not getting enough carbohydrates and that's what your muscles need for food."

Carb counting

Phelps won his sixth gold medal in Beijing in the 200m medley on Friday, and will be aiming to equal fellow American Mark Spitz's record of winning seven gold medals in a single Olympic games when he takes to the pool for Saturday's 100m fly.

He will break Spitz's 36-year record if his team qualify, and go on to win, Sunday's 4x100m relay.
The very process of challenging that record entails a hectic schedule of heats, semi-finals and finals.
Between winning his 10th gold medal in the 200m butterfly - which made him history's most successful Olympian - and his 11th in the men's 4x200m relay, Phelps had just an hour between races.

With that kind of turn-around, topping up his carbohydrate count is the key, Ms Lewin suggested. The copious amount of refined carbohydrates consumed in the bread and pasta he eats will digest quickly and give the swimmer instant energy.

Phelps, who weighs around 85kg (187lbs), understands this. Asked what was needed to continue his gold-medal winning streak, he said simply: "Get some calories into my system and try to recover the best I can." - BBC