This is an explanation of the Paleolithic Principle and my expectations of the Paleolithic diet.
First off we should get rid of the myth that Paleolithic people led short brutish lives. This statement is a general misunderstanding of the concept of life expectancy at birth and due to the bones found of paleolithic people.
Paleolithic people generally had much better bones than the neolithic and present people. A life expectancy of 30 does not mean that people lived only till 30 years. This means that average of the age at death of people was 30 years. Lots of children died within a couple of years after birth, which reduced at higher ages, but still significant number of children did not live past 15 years of age. After that death due to diseases and accidents reduces significantly. It is common to find men/women of age 80 years in hunter gatherers.
Also menopause which starts after 45 years cannot evolve unless people are living beyond the age of 50 regularly. It is an adaptation to reduce resource competition by taking females out of the task of producing offsprings thereby reducing the population, and provide help to the younger females so that the young ones can be cared for better.
There are two phases in human development. Before migration from Africa, and after. The adaptation made before the migration are common to all humans. Adaptations made after are not.
It is easy to recognize that humans migrated from Africa because the genetic variation in Africa are much more than elsewhere. Also the reason why humans have the huge number of sweat glands and very little hairs. This is because humans evolved in a hot and dry environment.
The diet prior to migration would be called the paleolithic diet. The later changes are due to adoption of agriculture. Where humans started to grow grains and legumes and drying and storing them for lean periods. This period is marked by higher consumption of grains and legumes and adaptations based on these.
There are controversies regarding Paleolithic diet. Paleolithic period human remains obtained are high in 15N Nitrogen isotope. Since these are high in grasses rather than other types of plant food, and humans cannot consume grasses, it was assumed that humans ate a lot of meat of animals that were eating grasses. But recently it has been discovered that there are some tubers that are high in 15N, particularly the tiger nut. It is possible and makes more sense that humans consumed these type of tubers as a majority of their diets. In fact some of the old African tribes use these as their staple.
Hunts are not always successful, and there are very few extinctions in Africa, so it is likely that humans evolved and became adept at hunting, while animals evolved in Africa to avoid getting hunted. When skilled humans moved out of Africa, they were a totally different beasts for the animals in the rest of the world and the animals could not adapt and were extincted.
So humans must not have obtained a regular supply of meat.
Also fruits in Africa are huge. It is very much obvious that humans obtained a large part of their calories from high carb foods. As an aside note that all long living populations at present are high carb, Okinawans and Mediterraneans; Okinawans more than mediterraneans.
We also know that Africans have a much longer colon, which means that humans had a much higher consumption of fiber. The fruits and tuber consumption would provide them with the high fiber content.
There is another observation. There is a bird called honeyguide. It has evolved along with humans and can guide them to beehives. The present African tribes use the Honeyguides to obtain a lot of honey during season. This results in a very high sugar diet during the season. The tribals do not suffer any harmful effects of this high sugar diet.
Hunts succeeded rarely, so meat was not a big part of the diet, but smaller animals could be caught regularly. So it was a regular part of the diet, but not a staple.
Fat is very difficult to obtain in the wild. Most of the plant foods don't have much of it. And animals in the wild don't accumulate much fat except during specific seasons or pregnancy. Many tribesmen try to avoid killing females, and particularly pregnant or mothers. This can be seen in meat preferences to this day.
Humans have been cooking for at least a couple of hundred thousand years.
Tribal people are not particularly known for their cleanliness. And this means that they get a huge amount of bacteria in their bodies.
To summarize paleolithic diet was based on real and whole food.
It was high in carbs, fibers and simple sugars.
It contained regular meat consumption but was not a major part of calories.
It was low in fat.
Majority of calories came from tubers, followed by fruits, and seasonally honey.
Grains were very rare and legumes were never dried. Legumes were part of vegetables.
Now the paleolithic diet ideas cannot be directly used in modern times.
It is difficult to get good quality honey for most people. Refined foods must be avoided including refined sugar. Raw cane sugar maybe ok, in small quantities.
Our digestive system can no longer handle huge amounts of fiber. Still its a good idea to determine how much fiber we can handle, and aim for that.
Meat and other animal products are good to consume regularly.
Grains and dried legumes should be reduced in the diet. Dried legumes are probably ok after sprouting.