15 August 2012

Evolution - Our Love Affair with Fat

When we take animals from the wild, we first see what their natural environment is, then we attempt to recreate it in order to keep them happy and healthy. Same goes with food. We have to give these animals the food they evolved to eat and the food they would choose to eat in their natural environment.
It is important to examine what isolated populations eat. I've already wrote about the incidence of chronic diseases in Africa, India and among the Inuit.

We should eat what we are designed to eat. 
No animal has to be told what to eat, how to eat, how much to eat. Primitive tribesmen don't walk around with calorie charts and personal trainers to guide them in the wild when choosing their food. They eat what they like. People who has not been educated in diet, has no trouble finding the right food.

Nature is really simple. There are 2 types of animals in nature:
  1. Herbivores that eat plants.
  2. Carnivores who eat herbivores.
All types of animals are identical. For instance, rabbits all eat grass, no matter where they are, or if they are pregnant. Similarly, you will never find a lion eating a piece of fruit after a heavy dinner of zebra fat. 

We humans, no matter what our skin colour is, or where we come from, as a species we all are Homo Sapiens. So we should all eat the same kind of diet.

What happens in nature:
Gorillas eat leaves, 90% of its food is water (it does not need to drink water), the rest is protein, carbohydrates and minimal amount of fat. So we would think that it is on a low fat diet. It's not as simple as that. The gorilla is a "hindgut digester". It works like this: the 70% fiber of its food is fermented by bacteria in its long cecum (appendix, ours is only a few inches long) and obtains short-chains fatty acids (saturated fat!). It then absorbs and uses this fat as energy. So we no longer have a low fat diet, but a 66% fat diet, the rest is a bit of protein and some carbohydrates.

If you feed a gorilla a low fiber (low fat diet) of fruits and cereals, it will develop the same chronic diseases as we have today, they get heart attacks and strokes like we do.

Carnivores and herbivores digestive system

Same for cows (ruminants), but they are "foregut digesters". Proteins, carbohydrates and fiber are fermented in the stomach and also produce short chain fatty acids. Saturated fat provides 70-80% of the cow's energy supply, the rest is protein, and NO carbohydrates.

Carnivores prefer the fattest parts of the animal (internal organs). Their energy supply is similar to the cow's: 70-80% fat, the rest is protein and no carbohydrates.

Humans: When they can get it, human primitives prefer their diet to be: 60-80% (in calories) fat, 20-25% protein and the rest carbohydrates.

Conclusion: All mammals are designed to eat a high fat diet.

Archaeological evidence:
Cave paintings show animals and people hunting them. There are no paintings with apple or olive trees.
The size of our enormous brain tells a lot about our diet. About 2 million years ago, our brain started to increase. The reason for this increase is "climate change": 
  • For 2.5 million years we had Ice Ages.
  • Long cold winters, short cool summers. For most of the year, there were hardly any plant foods available. These plant foods could not have sustained us for a whole year.
  • This resulted in a heavy reliance on animal foods. The animals in this cold climate were carrying a lot of fat to keep themselves warm. Our ancestors smashed the bones and skulls to get access to the marrow and brain (fattest parts) of these animals.
The bone marrow and brain consumed, contain 20-22 carbon fatty acids (AA, DTA, EPA, DHA). These are essential for brain development. Linoleic acid is the fat found in plants, these contain only 18 carbon fatty acids. Humans do not have the ability to elongate linoleic acid to a longer chain fatty acid. As ancient humans consumed the brain and marrow, they had the biggest supply of the long 20-22 carbon fatty acids required to build big brains. Our brain growth could never have happened without these fats.

According to Kleiber's Law, our brain and it's energy usage is enormous. We have to get that energy somewhere. So we need either a large gut with a large absorptive surface (which is not the case), or a very energy-dense diet. We do not have a long cecum (discussed earlier) to transform plant fibre to fatty acids, like gorillas do. We get very little energy from plant food. So everything we eat has to be absorbed by our small intestine, which is not big either.

Digestive surface of man and gorilla

This is what humans have:
  • A brain that uses 20-25% or resting energy.
  • A small gut.
So we need a very energy and nutrient dense diet. The only macronutrient that can produce that sort of energy, without eating huge amounts of food, is fat. The only practical source is animals.

Our love affair with fat:
These examples are not from scientific textbooks, they only reflect what people at the time thought about food.

The Bible
"And Abel was a keeper of sheep, but Cain was a tiller of the ground."
"And in process of time it came to pass, that Cain brought of the fruit of the ground an offering onto the Lord."
"And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the Lord had respect unto Abel and his offering."
"But unto Cain and to his offering he had no respect."
This tells us, that plant food was not as important as animal fat.
"And Pharaoh said unto Joseph...'come unto me and I will give you the good of the land of Egypt and ye shall eat the fat of the land.'"
                                                                       - Genesis
"And in this mountain shall the lord of hosts make unto all people a feast of fat things... of fat things full of marrow."
                                                                      - Isaiah
In the New Testament: When the prodigal son came home, his father killed a "fatted calf."

Scandinavian Eddas as Sagas:
"There [in paradise] the feast will be set with clear wine, fat and marrow."

The Vedas (India) talk about how fat meat, wild and domestic, are prized. There are also accounts of clashes between tribes protecting the land where wild game was available. The royalty of this period, who had constant access to fruits (sweet and acidic), had famous toothache. The Vedas mention about recipes to relieve pain and treatment for fruit induced toothaches.

Isolated populations:
We know about the dietary habits of Aborigines (Australia) from the accounts of Dr Carl Lumholtz (Norwegian explorer and ethnographer). 
  • Aborigines liked fat meat, and they ate the best parts first (organ meat and fat).
  • They never ate vegetables.
Few other examples of populations living entirely on animal fat:
  • Lapps and Saami
  • Siberians
  • The Inuit
  • North American Plains Indians
  • Marsh Arabs
  • Berbers
  • Nagas
  • Masai
  • Samburu
  • Gauchos
Professor John Yudkin summarizes this subject very well: "Fat is the most valuable food known to man."

Agriculture began at the end of the last Ice Age, 10,000 years ago. This was followed by the domestication of the animals.

  • Cereals outweigh all other food in out diet.
  • Bad jaw formations and cavities started to appear.
  • Since the beginning of the last century, a new disease became widespread: coronary heart disease.
We had to find the reason why. Ancel Keys, whose hypothesis was based on the idea that dietary fat was the cause of heart disease, in his report he took only the 6 countries which fit his idea. The problem was, that data was available from 22 countries, but he just ignored those which didn't agree with his hypothesis. That's were the French paradox comes from. In France, the consumption of fat is very high, yet the death from heart disease is lower compared to countries with a low fat diet.
"For a modern disease to be related to an old-fashioned food is one of the most ludicrous things I ever heard in my life."
                                                                                - Dr Cleave
The consequences of a carbohydrate based low fat diet, which is considered healthy today:
  • Obesity
  • Diabetes
  • 3 times as many cancers
  • Heart Disease
  • Brain shrinkage; A study published in 2008 shows how low levels of vitamin B12 (found only in animal foods) is linked to neurological disorders and smaller brain size. Vegans have the most shrinkage.
Civilized man is the Planet's only chronically sick animal. No wild animal or human culture living on its natural diet suffers the chronic diseases we do. Our pets suffer the same diseases we do, for exactly the same reasons. Unfortunately, wherever we travel in the world, we export our dietary dogma and make native populations as sick as we are.

The problem is that the food we are told to eat by health authorities, has very little similarity to what we adapted to eat.

The answer would be to go back to our ancestors diet:
  • fatty meat, fish, eggs
  • a bit of non-starchy vegetables and nuts
  • and even smaller amounts of fruits

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