I am sure it is a mixture. The most important thing is to eat a lot of calories. I am sure his metabolism is insane. One of the best ways to trigger testosterone from my research is full core power lifts and or sprinting. I believe it triggers a fight or flight response which encourages testosterone production. I could be wrong. I am curious where he gets his cholesterol because if I am not mistaken it is an important precursor to it. Although from a report I did about 10 years ago, I found a source saying T levels are a few percentage points higher in vegans and vegetarian than omnivores. I can't say much for that source I used, but I remember he referenced Carl Lewis a lot who was another famous vegetarian Olympian.