August Engelhardt was a German nudist who came to believe that all human illness could be avoided if you eat coconuts, and nothing but coconuts. It was part of his back-to-nature philosophy, although real human populations who depend on coconuts also eat other things. He eventually bought a coconut plantation in what is now Papua New Guinea, and invited his devotees to join him.
From 1902 to 1919, Engelhardt lived on a beautiful South Pacific island, eating nothing but the fruit of Cocos nucifera, which he believed was the panacea for all mankind's woes. Except that a coconut mono-diet proved to be a terrible idea. At the end of his life, der Kokovore was reduced to a mentally ill, rheumatic, severely malnourished sack of bones with ulcers on his legs. He was only 44.
Things didn’t end well for the other coconut cult members, either. Jesus said, "Man shall not live by bread alone," and Harry Nilsson said, "You put the lime in the coconut, and drink them both together." Read Engelhardt’s story at The Salt.
(Image source: Christian Kracht, author of Imperium)