The 38-year-old's regime is the stuff of legend and is something credited with his incredible longevity in the game.
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It is something his teammates also take notice of with goalkeeper Lee Grant revealing to talkSPORT he changed the eating culture in the Manchester United team when he arrived for his second stint.
Even his Portugal teammates are inadvertently 'shamed' into eating better, according to defender Jose Fonte.
The five-time Ballon d'Or winner has only been at Al Nassr for a matter of weeks, and the Saudi Arabia club's nutritionist is even amazed at how much body fat Ronaldo's teammates have already lost.
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However, not everyone can cope with copying the superstar's diet as Palmeiras defender Gabriel Menino found out.
"I called Mirtes, Palmeiras' nutritionist, and asked her to make me a Cristiano Ronaldo diet. I wanted to look like Cristiano Ronaldo," the 22-year-old told Palmeiras Cast (via A Bola).
"The diet was like this: breakfast was an egg and supplement. Pre-workout was a supplement, lunch could be grilled and salad. For breakfast it was more supplement, for dinner, again, grilled meat and salad, and before going to bed another supplement. That was it.
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"I was warming up and couldn't take any more running. I just thought, 'I'm going to die.' Five minutes into the game, I couldn't run anymore, I would need to be substituted.
"She [Mirtes] saw from above that I was not well. She asked the masseur to bring me gel and isotonic. I took advantage of the fact that Weverton was in attendance and consumed it."
It may be very restrictive, but it has certainly helped keep Ronaldo in optimum shape for his entire career.
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At 38, he's still firing in plenty of goals and has already netted eight times in just five league games for Al Nassr.