At 51, Jesse Itzler has already had a string of successes.
When he was in his 20s, he was a successful rapper, who appeared frequently on MTV. (His first single, "Shake It Like A White Girl," reached the Billboard Hot 100 chart in 1991.)
In his 30s, he became an entrepreneur and helped build Marquis Jets, one of the largest private jet leasing companies in the world, which he later sold to a unit of Warren Buffett's Berkshire Hathaway for an undisclosed amount. Itzler was also a partner in Zico Coconut Water, which was acquired by Coca-Cola in 2013 for an undisclosed sum.
In 2008, he married Spanx founder and billionaire Sara Blakely and by 2015, the couple became co-owners of the NBA's Atlanta Hawks. They also have four children together.
But Itzler says none of those successes would have happened without the strict diet and wellness routine that he has been doing for 30 years.
"For me, the No. 1 thing that has changed my life — and I know this sounds crazy — but I only eat fruit until noon every day," Itzler tells CNBC Make It.
Itzler says when he was 21, broke and living on his friends' couches, he read a book called "Fit for Life" by Harvey Diamond.
"I was about to run my first marathon and I wasn't a runner, so I looking for anything that would give me an edge," he says.
Itzler says the book challenges the reader to only eat fruit until noon for 10 days and then on day 11 go back to your regular breakfast.
"So I did it, and on day 11, after 10 days of fruit, I went back to my regular breakfast, which was things like oatmeal, eggs, bagel and bacon and I felt terrible and that was it. I never went back," Itzler says.
In "Fit for Life," which was first published in 1985 and re-released in 2010, Diamond promotes a diet based on raw fruits and vegetables, with fruits to be only consumed on an empty stomach in the morning. The book also says animal protein should not be combined with complex carbohydrates such as beans or whole grains.
There has been controversy over Diamond's Fit for Life diet, especially around the idea of food combining and eating food on an empty stomach. In a study published in the April 2000 issue of the International Journal of Obesity, researchers at the University of Geneva in Switzerland found that having a low-calorie diet with a mix of food is much more effective than eating foods in certain combinations.
And Erin FitzGerald, RD and assistant clinical nutrition manager at Lenox Hill Hospital in New York City tells CNBC Make It that while it's generally not harmful to only eat fruit until noon, she doesn't recommend it.
"I would never recommend that my patients eat only fruit until noon. If anything, we need to 'break' our overnight fast with protein and/or healthy fat. Fruit can be a healthy part of our mornings, but eating a lot of fruit in the morning can potentially harm some individuals — in particular, those who have diabetes or who are at risk for diabetes," FitzGerald says.
Still, Itzler says for him, when he eats only fruit until noon he experiences higher energy levels and thinks more clearly, because according to him it gives his digestive system a break. But there is no scientific research to back up what Itlzer says.
After 12 p.m, Itzler says he eats super clean meals that are 80% raw. But he does treat himself to an occasional pizza or sushi roll while eating with his wife and four kids.
Itzler isn't the only entrepreneur, who has experimented with fruit-related diet.
Apple co-founder Steve Jobs' was at times a frutarian, eating mostly fruit as well as some nuts, seeds and grains. Jobs' was inspired to do a fruit-based diet after reading the book "Mucusless Diet Healing System" by Arnold Ehret in college, according to Walter Isaacson's 2011 biography "Steve Jobs."
In addition to eating only fruit in the mornings, Itzler says another key to success is taking at least three hours a day for himself.
"Everyone's knee-jerk reaction is that they could never do that, but I think its really important to take 10% of the day for yourself because I find that it makes me super present."
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