One of the most popular diet trends at the moment is known as the “paleo” diet. Paleo; stands for Paleolithic; an era 3.3 million years ago, a time of cavemen who had just managed to start using tools made from stone. The diet intends to include only foods that these prehistoric humans may have ate, such as meat, fish, fruits and vegetables, but completely rules out any groups of food that are domesticated such as grains, dairy products and legumes. The whole general idea is that we were not evolved to eat these foods and so they cause havoc with our metabolism and so should be a no-go.
There are several other key flaws in the whole concept.
Number 1: it’s not just grains we have cultivated, human kind has had an impact on virtually every naturally growing edible plant on this planet
If you walk into any supermarket, fruit and veg shop, even one which is “organic”, it is highly likely you will see rows of perfectly formed, brightly coloured and unblemished fruits and veg, bursting with juice and flavour. You think they naturally grew like that? Even before our ability to genetically modify our produce, human kind selectively bred fruits and veg for years to alter the taste, texture and size. For example, look at the watermelon painted by an Italian artist of the 17th Century, Giovanni Stanchi and contrast this with the modern day watermelon. That is the difference that 400 years has played – so what can 3.3 million years do?
Modern day apples have been domesticated from wild crabapples from Ancient China. They were originally named crabapples as crabbe was the old English meaning bitter and have been grown and developed, over roughly 4000 years, into over 35 different types of sweet, succulent and juicy modern day apples, with varying sugar and acid contents to alter taste.
There are countless more examples, but to make the point, the nutrition obtained from eating modern day fruit would be very different from what the hunter gatherers were getting 3.3 million years ago.
Number 2: we have also been selectively breeding animals for higher produce for over 10000 years
Pigs, cows, chickens and sheep… some of the favourites of the dinner table. Millenia of domestication, selective breeding and arranged mating has given us species which provide us with plentiful meat supply, tender chicken breasts and succulent, juicy steaks.
Modern day selective breeding is highly efficient, and the turkeys in the pictures are the product of selective breeding of the last 50 years. Development of technology and science has allowed us to link distinct phenotypes such as weight or the ratio of lean tissue to fat mass with specific genes or groups of genes, further increasing the efficiency of our manipulations. Now, on average, only the top 1-2 % top yielding “producers” of our herds, flocks and broods are picked to reproduce and only those genes and traits are passed down to the next generation. However, a less strategic and well-informed, but similar, type of selective behaviour has been occurring for over 10, 000 years. The oldest evidence of meat domestication was found in China where fossilised remains of a bird species closely related to modern day chickens has been discovered. Since that time, we have been breeding animals to give us more, more, more. It doesn’t matter if the meat source is “organic” or “free range”, these eye catching ideas do not change the fact that the heritage of this meat is, fundamentally, unnatural.
A stone age diet would, also, undoubtably have included meat sources most people would never dream of consuming now such as insects, rodents and reptiles. I don’t see many paleo guidelines offering recipes for tasty spiders or snakes instead of steak or pork chops. Are we to believe that the animals that human kind have moulded into shape and sculpted to perfection over the years provide us with the same nutrition that hunter gathers would have obtained from their catches in the stone age?
Number 3: We are continuing to evolve and adapt
Evolution has continued, relentlessly, since the stone age. We are now able to process, digest and obtain nutrients from a range of foods that were key to the survival of some of our species.
An example is lactose, found in diary products such as milk, cheese and yoghurt. Now the paleo diet rules these out, claiming they are unnatural, but these have been staples in parts of the world with a domesticated dairy industry for around 10,000 years, and in these countries astonishing adaptations took place to facilitate populations to be able to digest and extract nutrients from dairy products: an obvious indication of the survival advantage that these substances could offer us.
All babies are lactose tolerant – they produce lactase – an enzyme which breaks down lactose into its counterparts, allowing all babies to thrive on mother’s milk. As we grow older, it used to be that we switched off the lactase gene, meaning that the lactose accumulated in our GI tract, was fermented by bacteria instead. This fermentation process produces accumulation of gas: the reason why lactose intolerance causes bloating, wind and stomach pain. Now, in just 400 generations, a strong selection pressure caused the spread of a single nucleotide base change. This single nucleotide base is not actually in the gene sequence but is thought to play a role in the switching of the gene from “on” in young children to “off” in adults. This change has reached 77 % of Northern Europeans in an extremely short time frame (in evolutionary terms) suggesting that it offered positive survival benefits, and increasing the likelihood of surviving to mate.
Now I am not denying that a diet without highly-processed food is healthy and that eating plenty of fruit, veg and whole foods has a whole array of health benefits. I am just pointing out that a diet, such as paleo, with extremely rigid rules about what qualifies as “natural” and “designed for us” is completely undermined by our years of manipulating the natural world to suit us. We have sculpted our environment and, in turn, been sculpted by the cultures we have created. It’s worked wonders for our survival as a species, and we should not demonise our ability to make wonderful new foods, some of which can offer many nutritional benefits.