Eats lot of fruit in his diet. A lot of raw vegans also look very good, but so do some omnivores.
He says that fruit + cold water showers are the key to not having wrinkles. Obviously it's hard to isolate those factors since there can be a million of other things.
Personally from looking at many people on youtube in the gym/vegan/omnivore channels I'm starting to suspect that massive doses of fruit might be a key to longevity. The sugars in fruit don't seem to be an issue compared to refined sugar since many raw vegans eat a lot of them and still look very good.
Also note that cooking destroys many nutrients in food, which is why the "raw" in "raw vegan" might also play a huge role.
Check out her, a 70+ years old raw vegan who looks 30: https://www.youtube.com/watch?v=O6oJA_xhTa8
Obviously even withing veganism there are thousands of different diet styles you can take (low fat, high fat, etc..) so I'd just like to point out that "he is vegan" doesn't say much by itself.