I have a hard time believing that fruititarianism could be healthy in any way. It seems like getting almost all of your energy from fructose and hardly any fat and protein (two of the 3 core macronutrients) could not possibly work. It makes me think of an article I read in the past 6 months about how zoo animals are having metabolic damage because the fruit we grow commercially is so high in sugar it's no longer healthy.

And this is purely anecdotal, but I watched a youtube video about a guy who went raw fruititarian for a few months, and his before and after photos were not inspiring. He lost some weight, but his skin and hair seemed fragile, and he seemed kind of lethargic and spacey in his after video.