Dominique Charriau / Stringer
Well, no, but he does apparently work out at least three times a week.
Earlier today, Zuckerberg held a Q&A session where he answered a bunch of questions people left on his Facebook wall and Arnold Schwarzenegger had a burning question.
"Mark, I always tell people that nobody is too busy to exercise, especially if Popes and Presidents find time," he wrote. "You've got to be one of the busiest guys on the planet, and younger generations can probably relate to you more than they can the Pope - so tell me how you find time to train and what is your regimen like?"
Zuckerberg confessed that he works out at least three times a week - often with his adorable pup Beast.
"Staying in shape is very important. Doing anything well requires energy, and you just have a lot more energy when you're fit," he responded. "I make sure I work out at least three times a week - usually first thing when I wake up. I also try to take my dog running whenever I can, which has the added bonus of being hilarious because that basically like seeing a mop run."
Here's Zuck's wife Priscilla with Beast: