The Palaeolithic Era began 2.6 million years ago and is associated with the use of stone, wood and bone tools. Our species, Homo sapiens, is thought to have appeared some 200,000 years ago in Ethiopia, overtaking the Neanderthal after a volcanic catastrophe in the Mediterranean some 36,000 years ago. We only began to domesticate animals and plants around 10,000 years ago, and by this time our species had also begun fishing and using fire for cooking.

As a result of our genetic history, we have a digestive system akin to the carnivorous dog, more physiologically suited to fat and meat consumption than the high-carbohydrate, high-fibre diet of vegetarian ruminants.¹ In addition, the larger brain of our species places extra demand on the diet, requiring more fatty acids and protein than the brain of our chimpanzee ancestors. This points to an evolutionary shift that was supported by a move towards the routine consumption of fatty meat.

There are different version of what our Palaeolithic ancestors ate depending on the period they lived in, the local climate, available resources, landscape and altitude, as there still is today between, say, the Australian Aboriginals and the Masai. Furthermore, the people of the Mediterranean region would have eaten a wide variety of seasonal leafy vegetables, shellfish, fish, nuts, fruit and game, while those in the cold Northern regions such as the Inuit, would have eaten considerably more fatty meat and oily fish, summer greens, and some stored vegetables or seaweed during the hard winters.

A diet based on hunting and foraging meant it consisted mostly of meat, fish, insects, fruit, nuts, seeds, tubers and wild grains such as oats, spinifex and barley. It was a high-fat, high-protein, low-carbohydrate diet. The subsequent change in recent history is marked by eating more carbohydrate and vegetable protein in the form of cultivated grains and legumes. This change also included the regular consumption of dairy foods in some cultures, less variety of foods overall, and less meat. For instance, until recently, people in villages in Greece ate meat as little as once a week, and the festival calendar meant the diet could be virtually vegan for several months of the year.

Hunter-gathering relied on seasonal availability and there would have been periods of feast and famine. The reality of the diet would have been a dominance of only a few foods for long periods of time, with the attendant danger of nutrient deficiency. Even in the case where there was plenty of game, the meat could become too lean as the animals hungered towards winter’s end.

It has been argued that a shift to agriculture was in fact the inevitable result of a rapid population growth which nature could not sustain, a force still relentlessly driving innovation and the search for higher yields in the agricultural sector. The positive side of farming was the production of a surplus of goods that could be stored or traded. This surplus created the conditions for stable civilisations with cities and bureaucracies, and of course standing armies to protect them.² This relentless population growth in cities has, however, brought the environment to the brink of collapse in our own era.³

The prevalence of chronic diseases also characterise the modern urban lifestyle with its staple diet of white flour, refined sugar and hydrogenated factory oils. The diet marks a recent shift of only a few decades—facilitated by industry lobbyists and marketers—away from the more wholesome traditional diets of the past. In fact, heart disease, obesity and diabetes were rare only one hundred years ago in advanced societies and have steadily worsened with the increasing consumption of ultra-processed foods that are simultaneously calorie-rich and nutrient-poor.

In spite of this poor diet, we still live much longer than our ancient ancestors, but we are supported to a large extent by medications that palliate chronic disease. Our ancestors would have been lucky to reach forty years of age in the harsh conditions of the Palaeolithic Era, subject to the many pressures of climate and the constant threat of predators. Nevertheless, there are still people living around the world today who live on diets consisting mainly of traditional wholefoods, and who achieve an age in the high eighties to nineties.

While a traditional diet and lifestyle is unachievable for most urban dwellers, the modern version of the Paleo diet has certainly become popular and the clinical results of making the effort can be impressive. In fact, it has been well-studied in relation to heart disease, obesity and diabetes and has been found to improve glycaemic control, reduce triglycerides, reduce total cholesterol, raise protective HDL cholesterol and reduce blood pressure. It can also reduce weight.⁴ Even after only two weeks on a Paleo diet, such benefits are evident when compared to, for example, a clinical diabetes diet.⁵

Even so, the ideology can be strict, and requires the avoidance of any food resulting from the cultivation of plants and the domestication of animals. This means emphasising a diet based on grass-fed meat, free-range poultry, wild fish, organic vegetables, nuts, tubers, seeds and fruit. Grass-fed or free-range meat is important because the animals consume omega-3 oils which are not  necessarily present in the feed used in feedlots. This feed, like the pellets given to farmed fish, is rich in omega-6 oils which emphasises the pro-inflammatory nature of the modern urban diet.

In addition, Paleo dieters should avoid genetically modified foods, refined sugar, factory oils and chemical additives. Beans, along with most other legumes, were supposedly absent from our ancestor’s diet and are considered not strictly Paleo; however, if you eat legumes then they need to be soaked first to activate them, since the seed coats contain protective enzyme inhibitors that may interfere with digestion. The same goes for nuts and seeds.

Small amounts of dairy may be eaten in a more permissive version of the diet in the form of products such as kefir, yoghurt and butter. Some fermented vegetables may be prepared and stored, and organic wine may be consumed in limited amounts.

Vegetables, leafy greens and fruit are to be consumed as raw and fresh as possible in order to limit the losses caused by cooking and processing, and if you grow them at home then you might consider the protein value of any insects found on them as well, such as snails. In fact, eat as many insects as you can just like in Thailand where cicadas, grass hoppers, crickets and spiders are available in the markets as snacks. You can also pick juicy grubs from rotten logs as the Australian Aboriginals do.

Try to remember that the goal is not to duplicate an ancient diet when only modern cultivars are available for most vegetables and plants, but to keep in the spirit of this diet which is rich in phytonutrients and as free from the chemical taints of modern agriculture as possible. Processing should be kept to a minimum, but we can still use our fridges to store food and use the stove to cook with, avoiding the obvious pitfalls of cave dining. However, we certainly make no concession for microwave ovens which destroy vital nutrients such as vitamins and enzymes.

There are a number of obvious reasons this diet is healthy when compared to the modern urban diet. Firstly, the problem with a diet based on farmed cereals is that it is high in carbohydrate, and if the grains are refined into white flour then their consumption encourages insulin resistance. This is partly due to the fact that processing robs the grain of important cofactors needed to support energy metabolism such as B-vitamins, chromium and magnesium, as well as enzymes, which puts a strain on the pancreas. Completely avoiding refined sugar (sucrose and high-fructose corn syrup) is an obvious part of any healthy diet, but does not mean all sugars are excluded. If you want something sweet, then you can still use organic honey and dried fruit.

Secondly, wheat, rye, barley, spelt, kamut and triticale contain the prolamins gluten (gliadin and glutenin) which should be avoided by those with coeliac disease. These grains are also implicated in common food sensitivity reactions (non-coeliac gluten sensitivity) which cause dysbiosis and leaky gut. Nevertheless, grains can be easily replaced by the nutritious pseudo-cereals quinoa, buckwheat, chia, amaranth, rice, wattle seed and flax seed.

Legumes present a different kind of problem because they contain high amounts of lectins which are implicated in damage to the intestinal epithelium in those people who are sensitive to them. This is why legumes are generally avoided in the Paleo diet, but soaking, sprouting and cooking them can reduce the activity of lectins.

Phytic acid is also considered a problem by Paleo purists, which is found in the hulls of nuts, grains and seeds. This is because humans don’t have the enzyme phytase needed to break it down, which is present in the gut of ruminants such as  cows and goats. Phytic acid binds to calcium, iron and zinc reducing absorption, a potential problem for vegetarians who rely on these foods, but one rarely seen in practice if you soak legumes and nuts. You should take mineral supplements away from these foods and consume fermented drinks like kefir and kombucha that have probiotic bacteria to aid digestion. Remember, the ancients pounded, ground, soaked and prepared most grains, pulses and seeds in order to make them more digestible and ensure survival.

Dairy food is an integral part of the urban diet today yet it is a common cause of indigestion due to lactose intolerance. This condition is caused by a deficiency in the enzyme lactase which is needed to digest milk sugar, causing fermentation of the sugars and the resultant symptoms of gas and bloating. Lactose intolerance is actually a normal state for weaned mammals; however, a genetic mutation around 10,000 years ago means that some lucky people have a greater degree of adult-age tolerance than others.

There are also common problem with milk proteins (i.e. casein), and if you have a lymphatic constitution with a blue eye, you will find that avoiding dairy often improves sinusitis, hay fever and arthritis. Nevertheless, if you want to eat dairy then it has to be whole and not low-fat which just contains extra carbohydrates and other dubious fillers. Fermented dairy is usually less problematic, but raw milk is unavailable in Australia unless you have your own animals. Pasteurisation is unfortunately necessary in big urban centres because not all farmers care about hygiene, and the supply chain can be long with many potential sources of contamination.

Another way to think of constitutional limitations, in regards to what foods we can or can’t tolerate, is in term of blood types. About half of the Australian population is type O and this is our most ancient blood group. It follows that type O is Paleo, best suited to a high-protein, low-carbohydrate diet, and an assessment of the diet of patients attending clinic routinely confirms that type O should try to avoid dairy and refined carbohydrates. Type A and B are more flexible than type O and corresponds to the last 10,000 years of an agrarian diet, while type AB is apparently a transitional type. It should be obvious, however, that there is no blood type adapted to the modern era of ultra-processed factory-foods, a fact reflected in the modern epidemic of degenerative diseases.⁶

Fats are another important matter to consider because they are crucial to survival, yet they have been given a bad name for decades in order to deflect scrutiny away from sugar, and simultaneously promote replacement factory fats. All processed fats like margarine and canola contain transfats and have the worst heart disease profile of all fats. Don’t be fooled by the saturated fat and cholesterol myth either; cook with olive or coconut oil, and not omega-6 vegetable oils. Your caveman ancestors preferred the fattiest cuts of the meat and greedily consumed the animal’s organs without ill effect, while rich organic butter produced by cow’s fattened on green mountain pasture has been prised for centuries. Even so, saturated fats were eaten in the context of a wholefood, high-fibre, largely vegetarian diet rich in protective omega-3 fatty acids.⁷ Try avocado, almond oil and flax in salads but protect them from heat and oxidation as they go rancid easily. Healthy oils also come from eating a variety of nuts and seeds, and wild, oily fish.

Finally, you should exercise as often as possible, drink plenty of water and get enough rest and sleep to recover, repair and build the body. Being active like a hunter generates feel-good serotonin as well as toning the muscles of the skeleton and internal organs. You may also join a group to exercise with because isolation is one of the key reasons for failure in dieting. It may be obvious, but you have to be fit to feel fit, so the big hurdle is always at the beginning; nevertheless, the benefits soon come in the form of enhanced health, mood and vitality.

For those particularly interested in adverse reactions to dairy food, grains or sugar, more detailed eBooks are available on this site for the price of a coffee and donut.

References

1.         Voegtlin W. The Stone Age Diet. New York: Vantage Press; 1975.

2.         Diamond J. Guns, Germs and Steel. London: Vantage; 1990.

3.         Diamond J. Collapse. Hippo Books; 2005.

4.         Klonoff DC. The beneficial effects of a Paleolithic diet on type 2 diabetes and other risk factors for cardiovascular disease. J Diabetes Sci Technol 2009;3:1229–32.

5.         Boers I, Muskiet FA, Berkelaar E, et al. Favourable effects of consuming a Palaeolithic-type diet on characteristics of the metabolic syndrome: a randomized controlled pilot-study. Lipids Health Dis 2014;13:160.

6.         D’Adamo P. Live Right For Your Type. Penguin Books; 2002.

7.         Simopoulos AP. Evolutionary aspects of diet: the omega-6/omega-3 ratio and the brain. Mol Neurobiol 2011;44:203–15.