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Comment by jere | Hacker News Reader

>Nutritional deficiencies came from the absence of fat and carbohydrates, not necessarily protein. Indeed, if humans eat too much meat, diarrhea usually ensues. And within weeks, they can develop protein poisoning and even die. “Because we humans are not fully adapted to a carnivorous diet, we simply cannot digest protein very well,” Lahtinen says. “It can be very fatal in a very short period of time.”

What? This seems flat out wrong. Carbohydrates are the only macronutrient you can live without. Regardless of the long term health outcomes, many people live for years on carnivorous diets.

The first sentence might be talking about our past digestive systems, but the rest is about the present.

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From what I've read, protein poisoning is supposed to be a result of _exclusively_ eating exceptionally lean meats (e.g. rabbit) at the exclusion of everything else for prolonged periods of time (such that your body reserves get depleted). Beef and pork have relatively high fat content so you'd be unlikely to develop it from eating them in modern high protein diets, and even on a rabbit-only diet, it's supposedly possible to minimize the risk by also consuming the animal's organs.

For what it's worth, I first heard of protein poisoning from a survivalist, who was talking about extreme scenarios where there's very few calories available for consumption at all (e.g. winter survival in tundra)

There are certainly other well documented cases of nutritional deficiencies caused by lack of certain foodstuff (e.g. scurvy in ships in the 15th century, due to usage of copper ware, which denaturates vitamin c) so it wouldn't be strange to develop other nutritional deficiencies with a highly unbalanced diet.

I think scurvy in the 15th century was due to not including anything that might have vitamin C in the provisions. It was scurvy in the 19th and early 20th century that was due to copper pots (no one noticed because ships were much faster so sailors didn’t get scurvy), the wrong citrus juice (I don’t recall whether they had lemon or lime juice but they had the one with less vitamin C and called it by the name of the fruit with more), tinned food (babies on land were getting scurvy because the canning process destroyed vitamin C and they were only fed canned food), and contemporary doctors not really believing that scurvy was caused by the deficiency of anything.

You may be right about the dates, I was going from memory so could be mixing up my sources. The part about doctors not being aware of vitamin c deficiency as a cause for scurvy definitely rings true for one story I read about a south pole expedition

EDIT: found the story here https://idlewords.com/2010/03/scott_and_scurvy.htm

I recently caved and watched the latest season of Alone, which takes place in the Canadian Arctic, on Netflix. It basically matches the non-canine related aspects of this article.

Contestants were sent home months-in, despite having excess meat stores from hunting/fishing, because of dangerous weight loss levels. They were literally starving to death even while eating excessive amounts of protein.

There’s a separate question of how “true” the show is (looking at you Bear Grylls!) but I believe the diet aspects were done in coordination with doctors.

I haven't seen the show, so I'm curious about what those contestants were eating. Did they eat the full animal, nose-to-tail?

Indeed. Folks were hungry - there was minimal waste.

Unless, by waste, you count eating the contents of another animal’s digestive tract.

You are right, in modern times, carbs are generally considered bad. But some people trying all protein diets do report diarrhea. Doctors don't generally refer to it as too much protein, though. They refer to the problem as too little fiber.

Also, some arctic explorers tried living on all meat, and suffered vitamin deficiencies such as scurvy. So, while meat is a complete protein, unless you are eating fresh liver meat from a fresh kill, you are going to need some source of vitamin C at the minimum. Except for liver, meat isn't actually a great way to get fat soluble vitamins either.

Be careful with liver if you get it from polar bears for instance. You could get seriously ill (even die) because of hypervitaminosis A.

'Rabbit starvation" https://wikipedia.org/wiki/Protein_poisoning

pemmican fixes it, a mix of 50-50 protein-fat plus berries.

Maybe the article was not clear enough, but what is correct is that you cannot eat only proteins to cover all your energy needs.

Significantly more than 50% (e.g. 2/3) of the calories you eat must come from either fat or carbs, it does not matter which, as long as it is not protein (it does not matter for preventing protein-caused problems; depending on what kinds of fat or carbs you eat, they might cause other problems).

A mixture like pemmican, which is 1/2 dried meat + 1/2 fat, has probably around 2/3 of its calories from fat, so it is perfectly OK as the only food for extended durations.

While the animals hunted by them did not have much fat in their meat, ancient humans usually took care to not waste the fatty bone marrow and brain, which were a major source of fat for them. Nevertheless, those animals still contained much more proteins than fat, so it is very likely that the humans could not eat all the meat, so they probably ate the best parts, leaving the rest to scavengers.

I have to agree with you. Having lived a zero-carb lifestyle for years in my late 20s (losing a ton of weight and becoming the most athletic I'd ever been in my life), either that line is patently false or I'm a super hero.

"zero-carb" may be true, but that does not mean that you have eaten only proteins. If that would have been true, you would have been dead.

The meat of most domestic animals is fatty, most cheese & other dairy is fatty, eggs have a lot of fat in the yolk.

Even if you did not eat any carbs, your food must have included enough fat to provide more calories than the protein content. Otherwise you would have had quickly severe health problems.

you're 100% right. I intentionally focused on higher fat foods.

The line in question:

> Because we humans are not fully adapted to a carnivorous diet, we simply cannot digest protein very well

So you spent years of your life eating nothing but meat, maybe eggs? You never had dairy, never had fruits (bananas, apples, oranges, lemon in or on something), never had vegetables (carrots, onions, leafy greens) in that time period?

I'm not the OP, but a ketogenic (very low carb) diet is not exactly uncommon these days.

I follow one myself (for health reasons, I have reactive hypoglycemia), and have done for a few years now. While it was difficult at the start, after a while you get used to it. And I lost a ton of weight without even trying.

I don't eat bread, fruit (barring a small amount of lemon/lime juice in food), or any grains or root veg (potatoes are worse than table sugar for spiking blood glucose!).

I do eat meat, eggs, and lots of low-carb veg - leafy veg, broccoli, cauliflower, asparagus, chicory, aubergine, courgette, peppers, tomatoes, carrots, onions etc.

I also eat plenty dairy too - cheese has no carbs, and a small amount of milk/cream has very little.

> I do eat meat, eggs, and lots of low-carb veg - leafy veg, broccoli, cauliflower, asparagus, chicory, aubergine, courgette, peppers, tomatoes, carrots, onions etc.

This is my point to the OP, if you're eating any of those things you are still an omnivore, even if you're a low-carb omnivore. They seem to be claiming to have been on a carnivorous (only animal products) diet for years.

It's by no means unheard of, all you have to do is type "carnivore diet" into your search engine of choice to get all the information your heart may desire.

The OP didn't say that though; they did say they had a zero-carb diet, but my interpretation of that was "very low carb diet".

They responded to a post about humans not being suited for carnivorous diets by saying they ate a very low carb diet, therefore that report about humans not being suited for carnivorous diets is wrong or they're a super hero.

So my question to them was what they meant by that. They seemed to be implying that their low carb diet was very high in protein and low in anything not protein, or their statement was a non sequitur.

During that time, you are correct, never fruit, no milk (I ate cheese but in very small amounts i.e. burger patty with a slice of cheese), very rare vegetables.

A typical day was: breakfast - eggs and bacon lunch - burger patty (or 2) and cheese, or 1/2 lb of carne asada dinner - ribeye steak

I only drank water during that time.

As happens way too often, the confusion is from pronoun abuse. "It" refers to protein poisoning, not to the set of all carnivorous diets.

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