Two-time UFC Heavyweight Champion, Frank Mir, was also a vegan for many years. The mixed martial artist ended up feeling weaker and suffered several injuries so he eventually switched to the Paleo diet. After several months, he began to build muscle and generally got stronger.
“You could try to do as much as you want in the vegan diet to try to get protein into your system, but there’s still nothing like certain forms of animal protein that the body really does need. So now I eat healthy,” says Mir, who continues eating the “caveman diet” and feeling better for it.