New York: Rafael Nadal blasted the current obsession with fad diets on Monday, especially the moves towards gluten-free eating popularised by Grand Slam rival Novak Djokovic.
Nadal, the world number two, insisted he has never been tempted to succumb to what he describes as a passing trend which will be replaced by something more fashionable in years to come.
"At the end of the day, all the small things can help if you don`t get crazy. I always had the theory that the most important thing is be happy, enjoy what are you doing, and be fresh mentally," said Nadal.
"If have the gluten-free diet or have the perfect diet or these kind of things, which are supposed to change you or be a big sacrifice, but mean you are not happy the rest of the day, not being fresh mentally because that`s a lot of effort for you, better don`t do it.
"Not all the players who had success had the same diet or had the same style of play. Everybody`s different.
"Now it seems like the gluten-free diet is great. After three years or four years we will find another thing that will be great, too. Then the gluten-free will not work anymore."
World number one Djokovic famously dropped pizza and pasta from his diet as he opted for gluten-free at the end of 2010.
The Serb then went on to lead his country to a first Davis Cup, claim three of the four majors in 2011 as well as rack up a 41-match winning streak.
On Monday, Venus Williams, playing in her 60th Grand Slam, said she too has adopted a vegan diet, a response to having suffered the fatigue-causing Sjogren`s syndrome.
But the 33-year-old confessed to some lapses in dietary discipline.
"I used to love steak, so I do miss that," said the four-time US Open winner after making the second round with a straight-sets win over Belgian 12th seed Kirsten Flipkens.
"I`m a chea-gan -- I cheat a lot. You see a picture of me eating the wrong thing -- that`s why I have already confessed."
Nadal, the 2010 US Open winner, started his 2013 campaign on Monday with a 6-4, 6-2, 6-2 breeze past American wildcard Ryan Harrison as he returned to New York after missing thr 2012 edition.
He spent seven months off tour with a knee injury before returning in February and going on to win nine titles and building up a 54-3 winning record.
Even in his darkest moments, the 27-year-old said he has never been tempted to tinker with his diet.
"All these kind of things that are news, I am not doing. I am happy with the normal diet. But I don`t say it is negative. I will say everybody`s free to do what he wants. Everybody are not working the same things," said Nadal.
"Nothing strange in my life. I practice. I go fishing. I play golf. I go party when I have the chance to go party. That`s all. Really normal guy, normal life."