I'm not defending the idea that Yoel- or any top level fighter is legit 100% clean- but I have a Latin client who is 60 and aside from just a little less muscle mass, looks like Yoel. Just shredded. Its insane. I worked on his forearm- its like working on an anatomical specimen. Every muscle group is overdeveloped and easy to see/feel since his body fat is so low. He's a firefighter and runs a crossfit gym, competes in some crossfit natl. championship games, placed in top 10 for his age bracket. I asked him about it- he said if he stopped working out and ate the same way he currently does he'd retain about 80% of his current look. He said his diet is THAT important to how he looks, even as he works out 6 days a week.
And then there are gaggles of designer and generic drugs that can do a lot of the same...