Now that diet seems like a one-way ticket to sicksville, but Nance's case was an extreme one. Everything he tried eating, from vegetarianism to the Mediterranean diet left him puking and unable to keep anything down. It was only until he solely ate raw meat that his health improved and he was able to survive.
Eating every part of the animal, Nance is able to have a nutritionally complete diet while, strangely, getting rid of his need to fart entirely. Oh yeah and he makes raw meat smoothies.