Paleolithic Diet

What exactly is the ‘Paleolithic diet’?

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

The ‘Paleolithic Era’ was the period commonly known as ‘the Stone Age’. It commenced well before modern people emerged from Africa and spread through Europe, Asia, Australia and the Americas (a migration that is thought to have begun about 130,000 years ago). It ended with the development of agriculture and the construction of the first cities about 10,000 years ago. During the Paleolithic Era, it is believed that rapid evolution of the human species was taking place. By about 40,000 years ago, our remote ancestors were virtually genetically identical to modern people.

During the Paleolithic Era, all people were hunter-gatherers, that is, animals were hunted and plant foods were gathered. Until about 10,000 years ago, no society existed that farmed animals or grew crops. So during the Paleolithic Era there were no crops of cereal foods such as rice and wheat — staples in most societies today — and no-one ate milk products or drank milk after weaning.

So what did our distant ancestors eat, if they didn’t have milk, milk products or cereal foods?

Many studies have been conducted to answer this question. The first point to make is that there was no single ‘Paleolithic Diet’: Just as desert Aborigines ate different foods to those who lived in temperate coastal areas or in tropical rainforests, so too Paleolithic diets varied considerably. The range of available foods varied not only geographically (ie, from one part of the world to another) but also seasonally. Unlike today, our early ancestors often had no choice but to eat the food that was available in season. Nevertheless, it is believed that our distant ancestors made use of a greater number of species of animals and plants than most people do today, and that this variety probably contributed to a greater intake of vitamins, minerals and other food constituents that may be important to health, such as antioxidants.

It is also appropriate to admit that we do not really know exactly what foods were eaten in the Paleolithic Era. The relative contributions of plants and animals to food intake are also not known: it is extremely difficult to accurately determine the food intake of people who are alive today, let alone those who lived 50,000 years ago! So that lessons might be learned from our early ancestors’ eating habits, the remainder of this FAQ uses the term ‘Paleolithic Diet’ (ie, singular) to refer to the likely common features of the wide range of diets that probably existed tens of thousands of years ago.

Based on the foods that were available at that time, and on the diets of modern hunter-gatherer societies (such as the Bushmen of southern Africa and Australian Aborigines), it is believed by many nutritionists that Paleolithic people ate a diet that was surprisingly high in protein — derived largely from meat and offal — compared to the typical, present-day, Western diet. Protein intake may have been up to twice as high as that of the average Australian today. It is also worth noting that the animals hunted by Paleolithic people were ‘game’ animals, and so would probably have been relatively low in fat. The fish and other seafood (molluscs such as oysters and mussels, crustacea such as prawns) that would have been caught by people who lived near the sea, rivers or lakes, were also relatively low in fat, and, in particular, low in saturated fat.

Some authorities believe that fat intake may still have been quite high — perhaps even higher than now — because much offal is high-fat and offal was probably eaten along with the lean muscle meat. But even if this is correct, the fat would have been mostly monounsaturated and polyunsaturated, not saturated. (The likely beneficial effects to health of relatively high monounsaturated and polyunsaturated fat intakes are not discussed in this article.)

The typical Paleolithic diet must also have included many primitive forms of leafy vegetables, root vegetables (such as yams and sweet potatoes), fruits, berries, probably some grass seeds (perhaps including the forerunners of the later ‘cereal foods’ such as primitive forms of rice and wheat), some nuts and (for the very brave Paleolithic person) the occasional taste of honey. Because much of the energy needed for hunting and gathering had to come from food sources other than cereal foods and milk-based foods (which provide much of our kilojoule intake) Paleolithic people must have eaten huge quantities of fruits and vegetables. It is possible that root vegetables in particular made a significant contribution to the energy needs of many early people. As a result, intakes of most essential nutrients and dietary fibre were likely to have been much higher than now, with one notable exception: average salt intake was probably no more than about one-fifth that of most Australians today. However, rather than being a drawback of the Paleolithic diet, this is regarded as being beneficial, because low salt intake is strongly associated with reduced risk of hypertension (excessive blood pressure).

So the Paleolithic diet was mostly meat, fruits and vegetables, with little, if any, cereal food and no milk or milk products. What is the significance of this to the health of people today?

The potential significance of the Paleolithic diet to the health of modern people is a topic of keen debate among nutritionists. Some argue that the Paleolithic diet was the diet that Homo sapiens consumed during the period of most rapid evolution, so it represents the ‘natural diet’. According to this school of thought, eating cereal foods and milk products is not appropriate today, because we did not evolve on diets that included large quantities of these foods. It is perhaps relevant here to point out that among recent hunter- gatherer populations there is an almost total absence of the diseases that afflict so many of us in developed, Western countries. Heart disease, cancer, obesity, diabetes, osteoporosis (chalkiness of the bones) and rheumatoid arthritis (among other diseases) were very rare among the Bushmen, Amazonian Indians and Australian Aborigines until they started to eat Western foods and adopt our lifestyles. However, not all Western, degenerative diseases come from our diet — many relate to lack of exercise, cigarette smoking, exposure to pollutants and so on. Nevertheless, adherents to the Paleolithic diet believe that lessons do exist for us from the Paleolithic (and more recent) hunter- gatherer diets and lifestyles.

So far the discussion has been mainly about older people. Is there anything about the feeding of infants during the Paleolithic Era that might be of relevance to the present day?

Infant nutrition in the Paleolithic Era was far more basic than now. Breastfeeding (currently recommended as the sole source of nutrition for about six months) was probably continued for several years. Of course, until recently, there were no alternatives such as cow’s milk, soy milk or artificial formulas. The ‘naturalness’ of breastfeeding, and its many advantages to both mother and baby, are fully recognised by nutritionists today. For example, one of Australia’s dietary guidelines is: ‘Encourage and support breastfeeding’.

So there is some evidence of health benefits from ‘more natural’ diets. What exactly do the Paleo enthusiasts recommend we should do to improve our diet?

Proponents of the Paleolithic diet believe that we should increase intake of lean meats (as mentioned above, all the meat eaten in the Paleolithic Era was game and therefore probably low-fat), offal, fish and other seafoods, eggs, fruit, vegetables (especially root vegetables, but not potatoes), berries and nuts (excluding peanuts). Of relevance here is that Australian beef and lamb generally come from pasture-fed animals and so are usually lower in fat than European and American meat (which comes mostly from grain-fed animals). It is also worthy of mention that Australia is a source of a true ‘game meat’: kangaroo meat comes from animals that have been hunted, not farmed. It is a red meat, with all the nutritional benefits of red meat (rich in protein, iron and other minerals and B group vitamins) but is lower in fat than beef or lamb, and has a more favourable ratio of polyunsaturated to saturated fat.

Foods recommended for exclusion from the modern version of the Paleolithic diet include sugar, dairy products (although some suggest that low-fat dairy products are needed for calcium), grains (including cereals, corn, breads, pasta), potatoes, beans, soy beans and lentils. The resulting diet would be high- protein, medium-fat, low/medium-carbohydrate, high-fibre, low-salt, and very rich in essential vitamins, minerals and antioxidants. Although it was not available to Paleolithic people, moderate alcohol consumption is regarded by many ‘Paleos’ as being compatible with good health while adhering to the other recommendations.

Are these recommendations supported by most nutritionists?

While recognising the basic healthfulness of this ‘modern day’ Paleolithic diet, many nutritionists question whether it would assist substantially in overcoming modern, Western health problems. Although there seems every reason to believe that the Paleolithic diet provided benefits to survival, at least during the reproductive years, that does not necessarily argue for health benefits in old age. Our diet-related problems show up mainly in middle age and beyond. It is highly unlikely that many Paleolithic people (or more recent hunter-gatherers) lived to the age when diseases such as heart disease, cancer, osteoporosis and rheumatoid arthritis became major problems.

It is also true that our remote ancestors must have been more physically active than most people are now. Today, most Australians can buy all the food they need at the local supermarket, or call into a restaurant while driving home from work and ‘pick up a takeaway’. If Paleolithic people wanted to eat, they had to walk to find plant foods and walk (or, perhaps more commonly, run) to hunt game animals. Analysis of skeletons of Paleolithic people shows that they were generally tall and strongly-built, as a result of their diet and physical activity. One lesson we can all learn from the study of our early ancestors is that the human body was designed for movement: we adopt sedentary lifestyles at our peril!

It appears that there are some unresolved issues about the relevance of the Paleolithic diet to modern-day people. How would you sum up the present level of agreement between the proponents of Paleo diets and those who are not convinced?

There are substantial areas of agreement between the proponents of the Paleolithic diet and the majority of nutritionists who have not (or at least not yet) been convinced that we should all try to become ‘Paleos’. For example, both schools of thought agree that increased intake of fruits and vegetables, and reduced intake of saturated fat are very likely to be beneficial. Everyone agrees that most people today need to increase their activity levels. But a majority of nutritionists disagree that reduced- or low-fat milk and milk products, cereal foods (such as bread, rice and pasta) and beans are inappropriate foods for modern people.

Another major problem with the proposal that ‘Paleo is the way to go’ is that in a world of six billion people, with the population projected to reach as many as ten billion by the middle of the 21st Century, it is not possible for even a large minority of people to adopt a truly ‘Paleolithic’ diet: there simply isn’t enough food of a suitable kind. There would also be massive disruption to the environment and to the current system of food production if most people stopped eating bread, pasta, rice, beans, milk and milk products, and significantly increased their intake of meat.

Although there is little doubt that the potential of the Paleolithic diet (or at least of some aspects of this diet) to improve the health of people in developed nations is worthy of further research, it is probably inappropriate (at least at this stage) to recommend widespread adoption of the diet. Increased fruit and vegetable consumption, a reduction in saturated fat intake, and increased moderately-vigorous activity are aspects of the Paleolithic diet and lifestyle that are highly recommended by virtually all nutritionists.