Comment by mrob | Hacker News Reader

Comment by mrob | Hacker News Reader

The argument for keto/carnivorous diet does not depend on human adaptation to digesting starches. I understood it as:

* Evolution works at the level of genes, not individuals. It will select for short-term reproductive success at the expense of longevity or quality of life.

* All living things evolve to avoid being eaten (at least while they have the potential to reproduce or aid the reproduction of their kin).

* Animals primarily defend against being eaten by fleeing or fighting. These defenses can be 100% neutralized by killing the animal.

* Plants primarily defend against being eaten by producing toxins. These defenses can be neutralized by metabolism, but evolution has no incentive to select for 100% neutralization. If 100% neutralization of plant toxins is difficult then dying young with a lot of children might be a better strategy.

However, there are plants that defend with spines/shells/hiding underground, and plants that produce fruit to attract animals for seed distribution, all of which change the selection pressure for toxin production, and any food may be healthful or harmful purely as a spandrel (a byproduct of evolution of some other characteristic). There are examples of human populations maintaining good health on a wide variety of different diets, so as is usually the case with nutrition, there are no clear answers.

These arguments are all interesting but I think most relevant is that the best nutrition science we have to date shows that a proper plant based diet is optimal for health & longevity. The plants and animals we eat now are radically different than the ones we were exposed to through most of our evolution so paleo proponents are chasing a lost world.

Actually, the representation of the ancestral diet being primarily meat is incorrect - outside of a few examples where there just weren’t many plants available. Largely, humans ate what they happened upon. Meat was a scarce byproduct of another predators meal. Ie we ate what the big cats left behind.

Furthermore, the ultra refined and concentrated foods we now eat didn’t exist until very recently. The amount of sugar cane needed to produce a single can of soda isn’t something any human would sit down to eat.

Edit-changed are to ate

>we ate what the big cats left behind.

humans can hunt

Humans evolved during the ice age. There were no vegetables in large enough quantities to feed the human brain's massive growth over the past million years. Every single paleolithic cave art depicts animals and hunting techniques. Fossil evidence from millions of years ago show bone scrapes on zebra and reindeer bones in human caves. We evolved to hunt wooly mammoths twice the size of elephants for goodness sake. We decimated whole populations of megafauna. You would have to go back 4-6 million years ago to find scavenger ancestors.

Cooking is very likely the reason humans suddenly had access to far more calories to support a larger brain. The idea that an organ like the brain that feeds directly on glucose was supported by animal fat and protein just doesn’t hold up to serious scrutiny.

The brain is incidentally 60% fat. And all the glucose the brain requires can be synthesized from lactic acid. There are entire societies that live off of 99% meat. They live their entire lives with almost no vegetable intake whatsoever, and their brains develop and function perfectly normal. In contrast, consuming too much glucose can wreak all sorts of havoc on the brain, spurring excessive consumption, type 2 diabetes, and has been linked with Alzheimer's.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577529/

https://www.nih.gov/news-events/news-releases/higher-brain-g...

https://www.alzheimersanddementia.com/article/S1552-5260(17)...

“Studies have shown that type 2 diabetes can be a risk factor for Alzheimer’s disease, vascular dementia and other types of dementia because cardiovascular problems associated with diabetes are also associated with dementia. These include:

Obesity Heart disease or family history of heart disease Impaired blood vessels Circulation problems High cholesterol High blood pressure Research has also proved that, similar to diabetes, glucose is not used properly in the brains of people with Alzheimer’s disease. ”

https://alzheimer.ca/en/Home/About-dementia/Alzheimer-s-dise...

I'm not sure of your point, because the parent comment mentioned animal fats and protein not being a primary food source for paleolithic humans and their ancestors (which is not what the fossil evidence shows AT ALL, we created spears and bows and arrows and various hunting strategies and tools that are well documented, for millions of years).

But with regards to your type 2 diabetes comment, type 2 diabetes is strongly associated with diet intake of excessive carbohydrates. https://www.ncbi.nlm.nih.gov/pubmed/30289048 https://www.ncbi.nlm.nih.gov/books/NBK499830/

You don't need carbs in your dietary intake. Your body can synthesize carbs from fat, just as it can synthesize fat from carbs.

There is no such clinical evidence. For example, the Sami of North Scandinavia have a 40% lower cancer rate than Swedish people do (who are pretty healthy by Western standards), despite getting the bulk of their calories from reindeer meat.

https://www.ncbi.nlm.nih.gov/m/pubmed/19186763/

The modern cow is not fundamentally different from the ancient Aurochs, or reindeer or bison that used to be consumed in large quantities. Sure cows have been selectively bred for docile behavior and varying amounts of lean and fattyness but genetically speaking they're extremely similar. Meat doesn't vary a great deal (which is why a lot of things taste like chicken).

Diet has relatively little influence on cancer. Diseases much more closely correlated with diet like diabetes and atherosclerosis are most effectively prevented with a plant based diet. Tribes like Inuit and Masai that eat mostly wild meats show advanced atherosclerosis at early ages and suffer from short lifespans.

Of course if you're eating supermarket meat then your diet is nothing like any kind of ancestral hunter.

I'd love to see your clinical research cited sources.

Meanwhile meat has not changed much at the cellular level in tens of millions of years. The only fundamental difference between modern meat and ancient meat is that our ancestors ate the whole animal, organs and all, and that's relatively rare in modern American diet.

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