Evolution shapes both the structure as well as the behaviour of animals. We are also animals and the result of evolution like other species. Our species was shaped over many millions of years during which we adapted and evolved to survive as hunter gatherers making use of the plants and animals in various environments. Despite the recent development of agriculture and a few thousand years of ‘civilisation’ we are still the same species that roamed the world as hunter gatherers for millennia, and we have not lost the appropriate features we evolved previously. So what does that mean for modern humans?

Let’s start with nutrition. Through the millions of years of human evolution our intestines evolved to cope with a varied diet comprising plants, seeds, fruits and, occasionally, meat from hunted animals. Human animals living near the shore would have also taken advantage of fish and shellfish. The human intestine has evolved to be able to digest this wide variety of foods. Easily digestible foods are dealt with in the stomach and small intestine; those components less easily broken down pass into the colon to be fermented by friendly bacteria. Through the activity of the colon ‘biome’ we have evolved to cope with otherwise indigestible foods such as seeds, fruit skins, nuts and plant fibres.

For the same reason that cows choose to eat grass and other plant materials because they have evolved to cope with this diet, we should eat the foods which we have evolved to digest. And, in particular, we need to eat foods that are best for all parts of the human intestinal system. Digestion provides us with a variety of substances – proteins, carbohydrates, minerals, vitamins etc that we absorb and which are essential to maintaining health. This includes the products of fermentation in the colon. To keep healthy, we need to feed the bacteria in the colon, and they will provide us with certain substances which we need for our health. We and the colon bacteria have evolved together: both of us thrive when fed correctly.