There are races of people who are all slim and who are stronger and faster than us. They all have straight teeth and perfect eyesight. Arthritis, diabetes, hypertension, heart disease, stroke, depression, schizophrenia and cancer are absolute rarities for them. These people are the last tribes of hunter-gatherers in the world. They share a secret that is over 2 million years old. Their secret is their diet - a diet that has changed little from that of the first humans 2 million years ago, and their predecessors up to 7 million years ago. Theirs is the diet that humans evolved on, the diet that is coded for in our genes. It has some major differences to the diet of today's "civilization". You are in for a few big surprises.

For millions of years, humans and their relatives have eaten meat, fish, fowl and the leaves, roots and fruits of many plants. One of the biggest obstacles to getting more calories from the environment is the fact that many plants are inedible. Grains, beans and potatoes are full of energy but all are inedible in the raw state as they contain many toxins and shouldn't be eaten raw as they can make you very sick. Many animals have adaptations that allow them to eat these foods in their natural state. Unfortunately humans don't.

Try this: Reach your arms out to each side, fingers extended. Imagine that the distance from finger tips to finger tips represents the millions of years of distinctly human evolution. Now, if you trim the fingernails of your right hand, the extent your reach has been reduced would represent the proportion of all those years during which people first started their transition from a hunter-gatherer economy to becoming settled cultivators of crops and farmers of animals.

Raise your arms again.  Look down along your arms to your hands at each side.  How important in your life, well-being, work and play are those arms, hands and fingers - and how insignificant for your life were those trimmed fingernails! In the same way, for the time of human evolution, our ancestors' bodies and physiologies were shaped in thousands of important ways over almost half a million generations and selected for those variations which fitted them best to thrive in their environment.

There is something wrong with our current view on diet and health. Nowadays, people often look at food in terms of how many calories it contains or whether or not it's "low fat" or "low carb", instead of aiming for real, nourishing food. Since the introduction of our current diet and health guidelines, along with the "Life, Be in It." campaign back in the early eighties, our health has been deteriorating and our waistlines bulging.

We need to look past the raw caloric value of the different macronutrients we eat at each meal (fats, proteins, and carbohydrates) and realise that they have different metabolic and hormonal effects on the body. It's far more important to get a lasting intuitive sense of how much of each macronutrient you need and when you need it (or not).

But how do you do that? How do you figure out the proper number of calories - and breakdown of fats, protein and carbohydrates - and what foods to obtain them from to accomplish your fitness and health goals? To lose fat? Gain muscle? Maintain status quo? Run marathons? Eliminate chronic or auto-immune disease?

In fact, most popular daily diets look at overall calories as the main factor in weight loss and weight gain. Conventional wisdom says that "a calorie is a calorie." From there most diet gurus generally prescribe some formulaic one-size-fits-all breakdown of fats, protein and carbohydrates. A classically trained Dietician or Nutritionist will tell you that protein should be around 10-15% of calories, carbohydrates should be 60% (and mostly from whole grains) and fat under 30%. This macronutrient breakdown stays the same regardless of how much weight you need to lose or what other goals you might have. This is then generally interpreted to simply enjoy things in "moderation", or have a "balanced diet".

Well, what is a balanced diet? As explained earlier, the balanced diet for our species was what we could acquire from nature thousands of years ago, not what the government and doctors tell us to eat now.  Be wary of the term "balanced diet".  It is a loaded label which can generally be taken as meaning a diet consistent with the preferences, prejudices and (limited) knowledge of the speaker. It is politically correct, bland, cautious, inoffensive and sensible; comfortably under the established status quo - but quite unrelated to the human genome and devised without any reference to human evolution. In fact it's a peculiar artefact of life in a wealthy corner of 21st century civilization.

Unfortunately, government authorities are bound to "take a balanced view" and so give weight to arguments from food manufacturers that the use of certain additives and manufacturing processes should continue, and to pharmaceutical companies who claim their drugs are more effective in treating behavioural disorders. A cynic might say that a "balanced diet" is one that is one third good for our physiology, one third good for business and one third good for our consumerist culture which condones damaging food and lifestyle choices as "little treats" which "all children deserve"!

The proper response to that problem is not to say "eat in moderation" or "don't be so fussy" or "that's what the experts said". Nutrition is a science: the human body is not mere subjective phenomena, capable of being stuffed full of anything without ill effect. As a matter of objective fact, some foods are healthy and others are not. As a matter of objective fact, some foods should be eaten in abundance, others in moderation, others rarely, and others not at all. The proportions may often depend on the individual, but even then, facts are facts.

In short, a person should fare better in perceptible ways on any diet worth sustaining. That knowledge should be the basis for the person's nutritional choices, not mere dogma. If a person has that knowledge, then for him to insist on his food choices - however fussy, however demanding, however contrary to conventional wisdom - is right and good. Such a person is acting in his self-interest, based on his own independent judgment. And that's a good thing.

This idea of eating was not designed by doctors, dieticians, the government or faddists, but rather by Mother Nature's wisdom acting through evolution and natural selection. The Primal Diet is based upon extensive scientific research examining the types and quantities of foods our hunter-gatherer ancestors ate, and is backed by a broader range of biological, metabolic, cultural and historical science than any other diet or eating plan.