I'm no expert, but I think it's a hoax. Isn't it very easy to get sick from consuming raw meat? All my life I've been advised to make absolutely certain that any meat I eat is thoroughly cooked. Maybe that's the myth, though.
Some meats are safe to eat raw if they are fresh enough and prepared correctly. My friends and I are fans of 'tartar' and have had the following meats raw: beef, kangaroo, ostrich, deer, cerf. French culture is big on cookings meats as little as possible. This makes the meat more tender and savory but requires better quality meat. There are temperature guides for every type of meat. Having said all that, do not eat undercooked chicken. You will contract salmonella.
It seems like he only really ate lamb, which I'm not sure carries the same issues as pork or poultry. As long as the meet is super fresh(and CLEAN), at the very least with beef, it doesn't hold any ill effects to my knowledge. Fresh, raw ground beef is actually delicious with saltines. Regardless, a diet derived specifically of one thing can't be healthy...right? I'm also curious on his fluid intake. Doubt it's strictly water.