Price theorized that the missing element in Western diets was vitamin K, which is acquired in high amounts from animal fats. Every traditional diet had an adequate amount of animal fat, either in meat they ate, raw cheese, or raw whole milk.
https://lpi.oregonstate.edu/mic/vitamins/vitamin-K
It seems animal (and human) fat doesn't store much Vitamin K which is why a steady dietary supply is necessary.
Also did ancient societies have higher average lifespans than today? I don't quite understand claims ancient people were healthier.. Of course modern lifestyles have severe inadequacies, but it's complex, and for example many Japanese have quite long life spans despite eating a lot of rice.
A Masai is probably healthier than a cliche westerner fueled processed carbs and sitting all day, but the latter will certainly live longer.
As for Japanese eating lots of rice, portion control ? I'd guess they get a large proportion of their calories from rice, but don't over-eat. I used to live in Thailand, Thais eat all the time, mostly carbs but small portions, and there are still fewer fat people than in the West.
Think obesity, heart disease and diabetes. These don't exist in hunter gatherer people alive today and there is no record that humans ever had these problems before agriculture and civilization. We are better at treating health problems when they do arrise but we also have health problems that are caused by our lifestyle.
Why do people get dental work? Because good teeth are a sign of good health. We have far more problems with our teeth than hunter gatherer people but you don't see it because it is masked by dentistry. We have problems with blood pressure but it's masked with statins. We have problems with blood sugar but it's masked by insulin injections. We have problems with fatigue but its masked by coffee and sugar. We have problems with our joints and well... we haven't figured out what to do about that one yet. The list goes on.
Also perhaps the Japanese have long life spans in spite of eating lots of rice. Wheat grains seem to be harmful, whereas rice is a neutral carb, and Japanese get plenty of animal fats from pork in ramen, raw fish, etc.
Ex: https://thriftynomads.com/how-to-be-a-frugal-foodie-in-japan...
While americans typically have a much higher proportion of food as carbs & fat vs protein & veggies.
Why the stress on "raw" cheese and milk? Heat-treated milk and dairy have the same amounts of animal fats as raw.
Edit:
Ah, I see:
The [Weston A. Price ] Foundation is an advocate for the consumption of unpasteurized milk, or raw milk. One of its goals is to remove health regulations requiring pasteurization of milk products, so that raw milk can be legally purchased in all states. Supporters of this campaign believe pasteurization removes or destroys beneficial parts of raw milk, leading to a less healthy product that is associated with numerous diseases.[14]
https://en.wikipedia.org/wiki/Weston_A._Price_Foundation#Act...
So the foundation named after the author of the book you discuss supports the idea that drinking raw milk is beneficial to health and that pasteurised milk causes disease.
To clarify, is this why your comment is talking of raw cheese and milk? Do you also believe that raw milk is healthier than pasteurised milk?