Something of a predicament for people interested in diets, is that the subject is often associated with unreliability. It is common knowledge that many flourishing diets are mere crazes, living their short lives on the placards of the tabloids – and as if that were not enough, many other diets have more or less degenerated into religious movements, eruptions of pseudo-science from the new age and alternative medicine movements.
This entails a twofold problem. Firstly, when people listen to bad advice, these bad diets can be directly detrimental for their followers. Secondly, these diets tend to cast a long shadow on any criticism of the reigning order, even when such criticism is firmly based in sound scientific principle. It is not uncommon, for instance, to hear representatives of Departements of Agriculture mention the paleolithic diet in the same breath as some obscure pineapple diet, only to dismiss them both as craze and vogue.
I notice the same phenomenon when I discuss these matters in public; many distance themselves without even hearing the arguments, just because criticism of poorly performed research so easily is mistaken for criticism of science per se.
Because of this, it is a necessity to firmly disaffiliate from pseudo-science, and make sure at all times we do not find ourselves pledging allegiance to doctrines.
Many craze diets are easily identified as such, but matters are complicated by the fact that some of these shady diets market themselves with roughly the same rhetoric as the paleolithic diet – which is definitely not shady. Allow me to concretize:
Primeval diet is the hypothesis that we, just like other species, have a digestive system which has been evolutionary adapted to a certain diet, and that that diet therefore is one on which we would thrive.
Evolutionary medicine tells us that given a certain environment, the individuals with the best adaptations to this environment will reproduce more than the ones less fit. Hence, the genes of the better adapted will gain in frequency. In the genetical sense, we are almost identical to humans living in the Stone Age. Since the food available constitutes a big part of the environment, it follows that healthy food should mean the kind of food which has been available in our environment while our genes were selected.
This is logic. There is also a certain empirical support for it; contemporary cultures of hunter-gatherers live in an environment very similar to the paleolithic one, and studies have shown that these cultures are more or less spared from many of our widespread disease.
As previously have been stated, my approach to diet and healthy eating is based on the paleolithic or primeval diet. I have maintained the same approach for several years, but although my starting-point has been the same, my conclusions have evolved. The task of establishing what foodstuff were readily available during paleolithic time is not a trivial one. One has also to decide how those foodstuff are best approximated with the ones available today, and estimate the effect of certain deviations from this ideal.
The above line of reasoning on evolutionary adaption could carelessly be summarized as a summon to eat “naturally”. This should be avoided, because a similar argument is common in less reliable diets, but then very often as a doctrine without the supporting theory.
There is fashion in diets, and right now many diets want to wear a paleolithic shroud. Vegan diet, fruiterian diet, Montignac, Lindeberg, many GI methods, the mediterranean diet, Atkins, Low-carb diets; they all claim to be primeval diets – but too often, the paleolithic approach is reduced to a thin coating of berries and nuts, painted on the same old myths. These myths and include delusions such as the common fear of fat, the admirance of dietary fibre and the unnatural disgust for animal foodstuff.
“Natural food” is a poor description of what we are looking for, because there is an abundance of natural plants which are outright toxic. So, is “primeval” cutting it for us? It could of course be misinterpreted too. We are not looking for the most primeval, but rather “best matching our level of adaption”. If we choose a too primeval diet, from which we have actually adapted away, we end up in trouble. For instance; we share some common ancestor with the zebra, but whatever diet that creature thrived on, it would definitely not be suitable for us today (and neither for the zebra, I might add).
Our culinary timeline contains a number of breakpoints. We and our predecessing species have introduced fire, cooking, animal products, cultivated grain, dairy cattle, margarines, industrial food processing and trans fatty acids, to name a few – and for each and every one it is relevant to consider whether we are adapted to it.
We have eaten animals for approximately 40 million years. Australopithecus (2.5 to 3.7 million years ago) ate meat. Fire has been used for 1.5 million years, and we have cooked for at least 800 000 years.
When we discuss paleolithic diet we generally refer to the interval 2.5 million years ago and up to 10 000 years b.C, when agriculture was developed.
Of course, adaptions have been made during all this time; not only in our genes, but also in the genes of our surrounding species. For instance, our cultivated fruits of today look very different from the fruit of our ancestors – and their nutritional content differs as well.
To put these figures in some kind of perspective, one can consider that most of the current genetic polymorphisms in the human genome are believed to have evolved during the last 50 000 – 100 000 years.
We can also study the contemporary, healthy hunter-gatherer cultures – and we find that they all cook and eat animals, although their diet varies a lot in other aspects.
Let us take a closer look on one of my examples of unreliable diets – the fruiterian or raw vegan diet. This is a very extreme form of veganism, which advocates a diet of fruit only. Fruiterians always make the “it’s natural” argument, and they claim that it is natural compared not only to processed food, but even cooked and animal food.
The fallacy committed by fruiterians is the one of looking for “most primeval” instead of “best fitting our level of adaption”. They actually argue that “natural food” would be a diet which looks like nothing our ancestors have eaten, at least since our common ancestor with the lemurs! Why stop there, I wonder? Why not just make a bowl of Primordial Soup for dinner?
But even when we accept that animal and cooked food is definitely a part of the proper paleolithic diet, there is still room for interpretation. How well adapted are we to dairy? How well adapted are we to grain? Are the differences between cultivated and primeval fruit so vast that fruit has turned detrimental for our health?
I mentioned that my conclusions have evolved, and I meant my view on details of these issues, not in the model itself.
All of the craze diets mentioned above differ from the diet which actually reigned in paleolithic time; they make compromises, and often the compromise is inclusion of some modern foodstuff. Examples include: quorn beef, bananas, low fat milk, potatoes, protein bars, canola oil, beans, whole-grain pasta, soy pancakes, and bacon.
Many diets trying to call themselves paleolithic are low in fat, and oddly enough it is common to advocate oils rather than animal fat; vegetable fats have not been used in large volume until the 20th century.
So is there any diet which matches the actual diet of the Paleolithic? Well, actual diet would of course have been different in different places; some lived inland and some by the sea, and up north animal food would have played a bigger role than near the equator.
Globally, the diet is believed to have included vegetables, fruit, berries, meat, fish, birds, eggs, mushroom, insects, shellfish, nuts and root vegetables, and, possibly, small amounts of seed and beans. The available food must have been seasonally varying. Most difficult to assess is the proportion between different foodstuff.
Original populations remaining in the 20th century have had very differing proportions of the macro nutrients (fat, protein, carbohydrates) in their diet, but they all seem to have been healthy; hence, I believe a healthy individual can choose these proportions to his liking, and still thrive.
Even if we stick to the above list of foodstuff, they will differ from the primeval ones. Plants have been cultivated and animals have been bred. What we know for sure is that no paleolithic man ate potatoes, wheat, corn, skim milk, lettuce, sugar, carrots, banana or oranges – because none of these existed in their modern form. Almost every kind of bean, grain, fruit, root vegetable and vegetable have been cultivated beyond recognition (berries excepted), and a major effect of this process is an increase in the amount of sugar and starch they contain.
The meats are not unchanged either. Animals which roam freely – fair game for instance – will maintain a high content of minerals and good quality of fatty acids in their meat, milk and eggs alike. Raised meat can differ greatly in quality in these aspects, often because the animals are fed the same cultivated grain we are.
Whether or not people of the Stone Age ate animal fat is an issue which has been debated a lot. Nowadays, we often refer to fillet when we say meat; many parts of the animal we don’t eat. In the Stone Age, meat and fish probably was eaten with all accompanying fat as well as with the guts; contemporary hunter-gatherer cultures are seen to prefer the fatty parts over the lean meat.
One can speculate on the priorities of our ancestors, but it seems unlikely they would spend too much time collecting grain (which was wild and smaller in size than the grains of our time). It is widely believed that grains where not eaten in any significant amounts.
It is possible that animal milk where harvested from time to time, but it would have been much richer in fat and nutrients.
Many think that low-carb diets seem strange and artificial, but it must have been the norm in paleolithicum – seeing as the grain, the root vegetables and the fruit were so relatively low in carbohydrates.
Thinking primeval, paleolithic diet means to reconceptualise all opinions on what is normal. We have lived our entire lives with a certain kind of diet, a diet which impregnates our entire society and has been impregnating it for generations. But this is not enough to make it normal, not for our digestive systems and our genes; for them, it is just a craze…