Twitter boss Jack Dorsey has revealed his hardcore approach to handling stress - including only eating once a day and fasting at weekends.
The 42-year-old CEO survives on a brutal diet and exercise regimen backed up by hours of relaxing meditation every day.
The billionaire also told how he has turned his back on warm showers completely and walks to work for an hour and a quarter after chilling ice baths to stay extra sharp.
Dorsey reckons his rigorous routine makes his days feel longer which means he sleeps better at night.
He shared the secrets of his lifestyle regimen on the Ben Greenfield Fitness podcast.
"During the day, I feel so much more focused. ... You have this very focused point of mind in terms of this drive," Dorsey said about having his only meal between 6.30pm and 9pm.
The world's "most eligible bachelor" - whose net worth is $5.3bn – usually has a meal of fish, chicken or steak with a salad or vegetables.
For a treat, he has berries or dark chocolate for his dessert with the odd glass of red wine.
However, on the weekend he ditches food completely.
"I'll go from Friday 'til Sunday. I won't have dinner on Friday. I won't have dinner or any meal on Saturday. And the first time I'll eat will be Sunday evening," he revealed.
"I've done that three times now where I do [an] extended fast where I'm just drinking water.
"The first time I did it, like day three, I felt like I was hallucinating. It was a weird state to be in.
"But as I did it the next two times, it just became so apparent to me how much of our days are centred around meals and how - the experience I had was when I was fasting for much longer, how time really slowed down."
Despite his billions, Dorsey doesn't have a personal trainer or even go to the gym - doing just seven minutes of cardio exercise per day using the Seven app.
Talking of his walks to work he said: "I might look a little bit more like I'm jogging than I'm walking. It's refreshing ... It's just this one of those take-back moments where you're like, 'Wow, I'm alive!'"
California-based Dorsey was vegan for two years but switched to the paleo diet after his mother pointed out he was turning orange from too much beta kerotine.
"Nothing has given me more mental confidence than being able to go straight from room temperature into the cold," Dorsey said of his ice baths.
"Especially in the morning, going into an ice-cold tub from just being warm in bed is - it just unlocks this thing in my mind and I feel like if I can will myself to do that thing that seems so small but hurts so much, I can do nearly anything."
To make things even tougher on his body, he has spent the the last three years alternating between his 37c baths and a 220-degree sauna for 15 minutes... three times a day.
In the past, Dorsey told how he also dealt with stress through Vipassana meditation during a 10-day 'retreat' where there's no reading, writing, or devices allowed. He often spends hours meditating.
"I've more or less kept up the practice of two hours a day," he said. "If you can just get 10 minutes, and sometimes that's all I can find, that's what I do."
