Just watching an Olympian in action is enough to make most of us feel physically exhausted. From the grueling training schedule to the strict health and fitness regimen, athletes never seem to stop.

But have you ever wondered how they fuel such dedication? And does all that exercise mean they get to eat whatever they want? We quizzed the experts on the food habits it takes to become an Olympian.

1. They eat. A LOT.

According to Dr Helen O’Connor, a sports dietitian who was in charge of the nutrition kiosk at the 2000 Sydney Olympics, it can vary dramatically.

“Generally they’ll consume around 1600 through to five or six thousand calories daily, depending on the size of the athletes,” she says.

Image: iStock

The average recommended calorie intake for women is 2,000 and men 2,500.

"Marathon runners who expend a lot of energy in distance and training will need more than, say, a shooter," Dr O'Connor says.

"Some athletes have to be more careful closer to the games as they have to 'weigh in' such as those competing in boxing, martial arts, lightweight rowing and even some sailing categories. While the latter don't weigh in officially, they like to manipulate their weight for balancing in boat to get the best result."

2. There is McDonalds involved.

After they've competed, of course. The best part? It's FREE.

"Walking through the front door [of the Olympic food hall] your eyes can’t help but dart directly to the free McDonald’s. At the beginning of the Olympics, the lines are short with a few weightlifters, track and field throwers and marathon runners frequenting the Big Macs," former Olympic swimmer Melanie Wright told news.com.au.

"But by the final few days when most sports are finished, they can barely keep up as each athlete lines up to order 27 cheese burgers, 40 chicken McNuggets, 12 sundaes and a Diet Coke before collecting the food and walking away without needing to pay."(Post continues after gallery.)

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It's also the perfect drunk food, particularly for swimmers who complete their events early on at the Olympics and can spend the rest of the time, ahem, enjoying themselves.

"Every day there is a new place to celebrate and it’s not uncommon to see a large majority of the swimmers from around the world in the dining hall pounding the free McDonald’s at 4am," Wright said.

3. Their food is just like yours.

There might be some protein powders and gels consumed mid-events\, but other than that, the diet of athletes largely comes down to healthy eating.

"A typical day of food for an athlete will be three meals plus mid-meal snacks like muesli bars and something to recover after training," says Dr O'Connor.

"It's healthy eating - fresh produce, fresh fruit and vegetables, lean meats like chicken. Carbs and protein are important for recovery, particularly for athletes that have multiple games like basketball.

"So depending on the type of training, bread, rice and pasta would be eaten in the few days leading up to the event."

4. No, they can't eat 'whatever' they want.

All that training doesn't guarantee them a free food pass.

"Athletes generally have a lot of lean mass for their general weight and a higher lean mass means a faster metabolic rate. A lot of them actually struggle to eat enough to maintain this," says Dr O'Connor.

And while it might sound like a dream for most of us, it's certainly not.

"Athletes have to be careful to fuel their energy budget to maintain the right weight and the majority of that fuel comes from healthy foods," she says.

"An athlete who has to eat a lot to maintain their weight has a bit more freedom to eat more 'treat' foods but there are just as many who have to be a certain weight and have to eat less."

Image: iStock

5. They do have treats.

Just like us humble non-athletes, cravings are unavoidable.

"I don’t eat ridiculous amounts of anything super bad for me, if I crave something I’ll eat it, because I know if I don’t, I’m more likely to binge," swimmer Emily Seebohm told Mamamia .

"If I think ‘Man I just want some chocolate’ and I don’t have it, the next day I could eat a block! I have a little bit and I’m fine. We need a lot of energy and I thought I ate a lot, but Mitch [Larkin, partner and fellow Olympian] will eat my plate plus another plate!"

6. They actually eat less just before the Olympics.

In the days before their Olympic event, their training will taper - which means their food intake has to also.

"For a lot of sports, they won't be training loads right before the games so when you taper training, you're expending less energy. Same when they're just hanging around the village," says Dr O'Connor.

"If they keep doing as normal then they will put on weight which could be detrimental to their game success. Food adjusts with their training."

Swimmer Cate Campbell ahead of the Olympics. Image: Getty