Says Robin Greenfield, quoted in "He forages all his food but calls your diet ‘extreme’/Robin Greenfield seeks to challenge ideas about what counts as normal food" (WaPo)(gift link).
I see that he's in northern Wisconsin, and he eats a lot of "wild rice, acorns, wild pecans, black walnuts, hazelnuts, plums, fish and deer."
How do you eat acorns? We could forage a lot of calories from our own little yard if we knew how to eat acorns. Hint: It's a lot of work!
By the way, I remember Euell Gibbons. He was big enough, back in the 1970s, to be satirized on "The Carol Burnett Show":


Lots more here, at 