But, according to ex-Manchester United goalkeeper Lee Grant, that is the lesson Cristiano Ronaldo taught the Premier League side upon arrival in 2021.
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Grant told talkSPORT: "Not one player touched the apple crumble and custard, not one player went up for that brownie.
"Everybody was sat down and one of the lads said to me, 'What has Cristiano got on his plate?'
"So we were having a little goosey gander at what he has got and obviously it is the cleanest, most healthy plate you can imagine."
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The truth is, Grant and his fellow United players probably knew the effects of junk food on peak athletic performance.
But sharing a changing room with Ronaldo is a hammer blow to any player's self-esteem.
Men across the world have been forced to stand next to the chiselled 38-year-old and ask serious questions of themselves in comparison.
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Ronaldo's incredible fitness regime is well-documented, mainly by himself. Is he allergic to wearing a shirt?
Even at international level, Portugal defender Jose Fonte has revealed Ronaldo inadvertently shames his teammates into healthy eating.
Fonte told talkSPORT in 2021: "We always have a look at what he's eating and what he's doing.
"You know he's the best and you want to replicate what he's doing because he must be doing something right.
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"Obviously as a rule he eats nice and clean, you know the nice quinoas and all this healthy stuff… A lot of eggs, sweet potatoes, the broccoli, he's into that."
Now, like celebrity PT Joe Wicks during the pandemic, Ronaldo is single-handledly transforming the overall health of Al Nassr.
His new Saudi Arabian club have already changed their ways as a result of the five-time Ballon d'Or winner's arrival.
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Al Nassr's nutritionist, Jose Blesa, told Spanish outlet Ideal: "I was uncertain, like everyone else, about what it was going to be like to work with him and if the club was going to change a lot, but I haven't found a more professional footballer than him.
"Every conversation with him is a learning curve. We met and talked about his diet, about how he understands the importance of this and rest for performance. He wears two rest meters: the ring and the bracelet. He is the first to arrive at training and the last to leave. Dealing with him is wonderful."
Blesa added: "Cristiano helps me a lot, because we can no longer teach him anything, but he creates a school around him. The rest of the players do what he does because everything he does is wonderful to improve his performance.
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"Since he has been here, all the players have trained more intensely and followed a stricter diet. I have not seen a club like this in which the players improve practically 90 per cent in their body composition every time I see them: they have less fat, more muscle and they do all the exercises at their fingertips. It is a luxury to work there."
But before anyone feels implored to buy a gym membership and join Slimming World, know this: even Ronaldo has his cheat days.
The superstar striker is known to reach for the balcalhau, a traditional Portuguese meal made up of dried and salted cod fish, typically served with potatoes, onions, hard boiled eggs, olives and olive oil.
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And Ronaldo's Kryptonite? Steak with chips and a fried egg.
Maybe there is hope for the rest of us after all.