Since its hard for some people to tell how much of what Gatis says is true and how much of it is bullshit (HINT: vast majority falls into the latter category) I decided to review various bits of his diet advice and try to sort the reasonable stuff from the dumb shit. I'll be talking about these things one by one, starting from what I find the least crazy to the most crazy.
As a disclaimer: I am not a doctor or a dietician, my opinions are based only anecdotal evidence and whatever I can find on Google. But I can 100% guarantee that I am exactly as qualified to speak on this topic as Gatis, and I could probably do more pushups than him.
Raw Beef: Actually not that bad for you. Often people will leave a fair bit of redness in their beef even when they cook it, it makes it nice and juicy! Health risks associated with this are pretty low. Beef is usually considered the safest meat to eat rare or even raw. Steak Tartare is considered a delicacy even in the most tight-assed Western countries.
Raw Eggs: Any kid whose ever eaten cookie dough can tell you a raw egg or two won't hurt you. Even groups that usually air on the side of caution like the CDC or the FDA say the risk of getting sick from them is pretty low as long as the animal is healthy. Shit, Rocky did it, and he's got like seven movies!
Various Organs: This is a gray area. Most organs are considered perfectly safe to eat except for a few notable standouts. Liver, sausages and kidneys are a good example of organs that have reached a certain level of popularity in the states. If the livestock wasn't healthy, though, it can be a bit riskier, and some might like the taste a lot less than muscle meat. For the most part, the only thing you really have to worry about is gout. Thankfully, gout isn't fatal or anything and usually clears up on its own. If you get gout, you can just start a YouTube LP channel or go to the prom with your asian girlfriend and dance through the pain.
Blood: Surprisingly, it isn't uncommon for people to eat and cook with blood. Its very rich in iron (it figures, since that's where it goes.) The only probably is its a little too rich in it, and can lead to problems like diarrhea, vomiting and hemochromatosis. It's like the old saying goes: too much of a good thing is always bad. Plus, making blood a regular part of your diet makes it harder to tell you apart from a vampire, which is very inconvenient for monster hunts.
But as an aside, there's absolutely no validity to Gatis' theory that blood is the *only* ways humans are supposed to hydrate. Carnivores of all kinds drink water, and blood doesn't hydrate you very well at all. Its full of sodium and other shit that dries you out more than anything. Water is perfectly fine. Drink it.
Bones: I mean, you could eat a bone whole with no ill effects except maybe hurting your teeth? Raw bone tastes like shit and is about as easy to chew as pebbles, but you can do it just fine. Cooking with bones, on the other hand, is an awesome idea because it enhances flavor and reduces waste. Chefs can also do really amazing things with bones, like make jelly and broth. You put that shit in with some meat and a potato? Baby, you got a stew goin'.
Interesting, I've been told Gatis actually got sick from eating rotten bone marrow once, so this is one case where we might actually disagree on the safety of something in the other direction. To his credit, carnivores often leave the bones of their prey sitting around uneaten.
Unpasturized Milk: We're officially into "dumb" territory now. For the most part, unpasturized milk isn't super dangerous or anything. It carries a much higher risk of salmonella and other non-fatal illnesses. The reason I think its dumb is because the tradeoff for shitting like a firehose is untreated milk is *slightly* higher in certain enzymes and vitamins. However, the amount you get from it is so negligible it can be dwarfed by that pair of chicken eyes you just munched. It isn't worth the risk for virtually no reward. Plus, the only truly "natural" way to drink milk is straight from a woman's juicy titty. But a carton of milk is much cheaper than a big titty goth gf so we'll move on.
Antinutrients: Not a food per se, but something Gatis talks about a lot. I was surprised to find out this was a real thing, and then totally unsurprised to find that they're in such minuscule quantities in most foods you'll never have to worry about them unless you're already malnourished. I don't know about you, but when I'm starving I don't jump for a raw potato. Cooking seems to completely eliminate this problem for most problematic foods, and "antinutrients" aren't even always considered bad. If you're really concerned about it, eating a single raw egg is enough to offset any threat you might have. Its that insignificant.
Raw Pork/Poultry: The good news is that thanks to new meat industry standards, you can cook both these meats to a much lower tempature. The bad news is, eating them raw still runs a very high risk of giving you a stomach virus even when the animals are healthy and live a good life in a clean living space. Bacteria loves raw white meat even more than Tyrone does. It probably won't kill you or anything, some cultures even do it as a treat, but IMO it's not worth the risk. Besides, raw beef already tastes better.
Brain/Spinal Tissue: DON'T DO IT NIGGA. Sometimes brain is edible but even in those cases its so densely packed with cholesterol (which in moderation is good for you, but this shit has way too much) that it can make you very sick or give you a heart/blood condition if you're not careful. Plus, there's a significantly higher than average risk of catching a prion, which are always fatal and have no cure. Even if the risk was one in a million, it isn't worth it, because a prion is an especially horrible way to die. But if you're sure the brain is clean, I guess eating a little head cheese once in a blue moon won't kill you.
Rotten Food: Come the fuck on. You know that shit is bad for you. If eating a sick animal is dangerous for you, imagine how bad a dead animal whose bacteria and toxic fluids have been allowed to fester and rapidly expand. Imagine that shit with no kidneys or liver to filter it. The horrific smell and awful taste should be enough to drive you away. Gatis is only able to handle this shit because he has pica. That's why idiots who try to imitate him in this regard often end up vomiting their guts out before they even get a second bite in.
Human Flesh: Not only is eating other people a rude thing to do, it's also totally unhealthy! You know how I said the rare risk of contracting a prion from eating brains/spines invalidated any potential benefit? Getting a prion from eating human meat isn't even rare, its a fairly common reaction! When an animal eats its own kin, bad juju goes down. There's a reason the Donner Party didn't get very far out of the mountain.
Overall, my research into this stuff actually surprised me. I was pretty impressed with how many mainstream sources that are widely considered reliable actually supported and even encouraged a lot of the stuff from the top half. One recurring theme I saw though was how many of these foods are very high in nutrients. Often, too high. Blood has a ton of iron to the point where it can give you iron poisoning. Liver is full of Vitamin A, but you'll end up pissing most of it out. This brings us to the core problem: how "nourished" do you have to be? Are you so diabetic that you need to get half your body weight in animal corpses to get the vitamins you need to not fall over and die on the spot? How much of a good thing is too much?
If we went by the logic that "more nutrients = more power!" then fat people would be the most healthy motherfuckes alive. You could argue that they only got fat because of all the vegetable oils, sugars, preservatives and "antinutrients" but try binging 8000 calories worth of raw meat every day for a month and see if you don't balloon up. Moderation is key,
The big takeaway I got from all this is that Gatis is building his entire worldview from a very mainstream fad diet called "Paleo" that many people already take part in and talk about online. Gatis just takes regular Paleo Diet principles and mixes them in with his own special form of pseudoscience, spiritual woo and general insanity and sells it as some kind of new, enlightened thing instead of a narcissistic rebranding of an existing thing with tons of shit he just pulled out of his ass. If you're a fan of Gatis, you've been conned by a crazy person. He's not telling you anything you can't get elsewhere, uninfected by the taint of woo peddling. Don't walk away from Gatis. Run away.