The human brain is a biological enigma. Compared to our modest body size we have the largest brain in the animal kingdom. Brains are energetically expensive organs that require disproportionate quantities of dietary energy to support them. Paradoxically, we appear to have simultaneously evolved shorter guts. Whilst this made it easier to become bipedal it also limited the amount of nutrients we could absorb. This poses a conundrum for evolutionary biologists – what changed to allow us to achieve these contradictory feats? It must have been something unique as it has only happened to one species in the whole of evolution. The main theories are:
- Increased meat consumption
Brains need high levels of long chain polyunsaturated fats to develop – DHA & EPA – which were only available in quantity by eating meat, fish and especially the brains and marrow bone of large mammals. There is increasing archaeological evidence that early hunting and butchery were directed at harvesting just such nutrients.
Cooking allows far more nutrients and calories to be extracted from food. Cooking is a wholly human activity which is hypothesised to have created a need for complex social bonds not found elsewhere in the animal kingdom. This theory is expounded brilliantly by Richard Wrangham in his book “Catching Fire: How Cooking Made Us Human“.
Developments in this field of research are very relevant for those of us interested in eating a diet closer to that of our genetic make-up, our so-called ‘evolutionary diet’. So I was pleased to see an article about such research in the Guardian today.
Recent research in the news
Whilst there is little argument that palaeolithic man used cooking and hunted large game, it is not clear how far back these activities go. Wrangham argues that cooking must have started with Australopithecus coinciding with the beginning of the rapid brain development, but many disagree – there just isn’t evidence.
However, recent developments in the field have pushed back the dates of both cooking and large organised hunting.
Studies of 500,000 year old stone flakes have proved they were used as spear tips. This is 200,000 years earlier than previously thought, indicating an advanced hunting culture. Such weapons are sophisticated, requiring cooperation to produce. Such skills needed to be passed from generation to generation.
Even more impressive is evidence that cooking took place 1 million years ago. This is right in the middle of the period of rapid brain evolution.
So much for raw-food veganism!