Gearing up for the Olympics, athletes are powering down anywhere from 6,000 to 10,000 calories a day. But what does that look like exactly? Britain's National Health Service (NHS) spells it out, with the added note to not try this diet at home.

While American swimmer Michael Phelps said he gulps down some 12,000 calories a day of fried egg sandwiches and pizza during training, the typical athlete follows a stricter regime of complex carbohydrates and plenty of lean proteins.

Complex carbs and lean proteins make up the bulk of many athlete's diets. Image: Dusan Zidar/shutterstock.com

If you're a male Olympic heavyweight rower, this is what your diet might look like, if you're training three times a day, according to the NHS:

7 am: breakfast
• large bowl of cereal, such as porridge, muesli or Weetabix
• half pint semi-skimmed milk plus chopped banana
• 1-2 thick slices wholegrain bread with olive oil or sunflower spread and honey or jam
• glass of fruit juice
• 1 liter fruit squash (concentrated fruit mixes)

8 am: training
• 1 liter sports drink during training

9.45 am: post-training second breakfast
• portion of scrambled eggs
• portion of baked beans
• 1-2 slices grilled lean bacon
• portion of grilled mushrooms or tomatoes
• 2 thick slices wholegrain bread with olive oil spread
• 1 liter fruit squash

11 am: training
• 1 liter sports drink during training
• 500 ml low-fat milkshake after training

1pm: lunch
• pasta with bolognese or chicken and mushroom sauce
• mixed side salad
• fruit
• 1 liter fruit squash

4 pm: training
• 1 liter water or sports drink during training

5:30 pm: post-training snack
• large bowl of cereal with half pint semi-skimmed milk, or 4 slices toast with olive oil or sunflower spread and jam with large glass of semi-skimmed milk
• fruit
• 500 ml water

7:30 pm: dinner
• grilled meat or fish, such as salmon, tuna, chicken, or lean red meat
• 6-7 boiled new potatoes, large sweet potato or boiled rice
• large portion of vegetables, such as broccoli, carrots, corn or peas
• 1 bagel
• 1 low-fat yogurt and 1 banana or other fruit
• 750 ml water and squash

9:30 pm: bedtime snack
• low-fat hot chocolate with 1 cereal bar

10:30 pm: bed