I have a friend that's a "fruitarian" (he's been convinced that humans are frugivores by the influencers.) He says he loves pooping, which he says he does about 6 movements a day.
I've tried to explain that we're omnivores and high fruit diets are clinically proven to not be healthy long-term... Dude is skin and bones (he's literally wasting) and won't listen. He'll eat some veggies, but only raw. He avoids anything cooked in anyway because 'cooking stuff creates toxins and causes disease/cancer and other animals don't cook their food.'
Nutritional science suggests 9-12 servings of fruits and vegetables daily, but the limit for fruit is 4-5 servings (while there's no drawback to additional vegetables, but it's also not significantly (statistically) healthier). Fructose does funny things to metabolism for reasons we don't fully understand (many claim it acts like a hormone), but the fiber seems to help, though. Juices should be highly limited and basically treated as refined sugar. Science also strongly suggests properly cooking foods....
Eating lots of(or exclusively) raw fruit will most likely result in poorly/partially digested diarrhea, roughly apple sauce consistency and generally still looks more like food than poo(which describes my fruitarian friend's BMs, which he doesn't find problematic, apparently he considers it a feature and not a bug -- short intestinal transit time is point of pride for him, for some reasons, basically... he thinks if his poop stays in him too long it becomes toxic, so he thinks a normal healthy stool is toxic).
Long term risks include severe nutrient deficiencies that may carry with them permanent physiological damage. Yet he still isn't convinced by the numerous clinical studies on this ... Then again, he also thinks WiFi is unhealthy for some asinine/dubious reasons so he turns off his router at night so it doesn't disturb his sleep (his roommates plug it right back in, lol.)
He used to eat normally and supported Bernie Sanders. Now he's technically a raw vegan(he calls himself/humans in general frugivores) and believes so much dumb shit(anti vac, no longer respects trans pronouns, etc), and obviously he started supporting MAGA/Trump, so we don't talk much anymore.
The problem with realizing that you have cognitive impairments is that you have cognitive impairments. It's a vicious cycle I've sadly seen in multiple raw vegans. The longer they do it, the crazier(delusional, disordered) they get. Like my fruitarian friend doing weeks long water fasts as well.... He looks like someone with severe anorexia/bulimia. But oh boy does he pack it in! And within hours it's squirting out the other end. He's one of those people that don't fully close the bathroom door. So everyone can hear the squirts and splashes! Still less annoying than being lectured to about eating healthy by someone as clueless as they are confident.... Plus his 'shit' doesn't really stink, as it's not digested. Another point of pride for him.
We've evolved to eat cooked food. Please cook your vegetables, people. Salads are fine but most of our veggies will be very much more digestible and nutritious after being cooked! Some ruffage/raw plants are beneficial, though. Other animals need to chew chud basically all day to meet basic nutritional needs from vegetation. We have cooking, and it's awesome.
