“Life is a contradiction present in things and processes themselves, and which constantly originates and resolves itself; and as soon as the contradiction ceases, life too comes to an end, and death steps in.” I was reminded of this quote by Frederick Engels when I started thinking about the recent ‘Prevention of Cruelty to Animals (Regulation of Livestock Markets) Rules, 2017’ notification by the Government of India.
My own contradictions: I am a Hindu albeit a non-practicing one, I refrain from eating animals that are known to have nociceptors, and I oppose governmental imposition of any dietary restrictions in India.
So after some thought, I decided to discuss the science of meat, more specifically the effect of meat on our brains, evolution and the future, rather than analyse my own dichotomous beliefs.
We would not have been human without meat
Early on, in the six million years of human evolution, our ancestors were essentially vegetarians. A change in our dietary practices came about around 2-2.5 million years back. Research has now proven that the size of our brains increased exponentially only after we turned carnivorous. There are several reasons why meat helped us become what we are today, and much smarter than other primates like chimpanzees.
First: the vegetarian diet did not provide the energy and key nutrients as efficiently, or in as much quantity, as meat did. The brain of the modern human has a very high energy requirement. Second: the gastrointestinal tracts of early humans used to be much larger to help digest fruits, leaves and roots, and had a very high energy requirement as well. So as we changed our diets, our guts became smaller and the brains, much bigger, by preferentially receiving a higher percentage of energy from our diet. The fact that we became more adept at using tools and started cooking also helped.
Recent history and the future
Delhi University professor D.N. Jha received death threats after he published a controversial book in 2002 called ‘The Myth of the Holy Cow’. The book documented the results of his rigorous scholarly research about the dietary preferences during the Vedic times. He wrote that cows were sacrificed and beef was eaten during those times. If we are to believe him, about 30% of Indians have turned vegetarian since then.
India has the world’s highest rate of vegetarianism. In absolute numbers, it has more vegetarians than the rest of the world combined.
So humans’ recent nutritional history throws up a few questions. Did the meat-eating habit of a few thousand years back fuel further evolution of our brains? Does a meat-eating habit remain important for us humans to develop our brains even further? And if all Indians stopped eating meat for long, will there be an appreciable difference in the size of our brains as a result? Will our intelligence remain comparable to that of the others who remain carnivorous? For one, the Government of India notification seems to go beyond just beef. If strictly implemented, it may impact other meat-eating habits and even hamper the availability of other animal protein sources like milk.
The answers to these questions are less clear and not well studied. A hypothetical assessment would be that a few thousand generations of dietary practices may perhaps have an impact – rather than those of merely a few thousand years.
Recent research is beginning to throw some light on whether eating meat during pregnancy impacts the development of the foetus’s brain. As the brain slowly develops during a normal and uneventful pregnancy, it becomes more complex and mature. A recent study utilised innovative neuroimaging techniques and found that iron deficiency in mothers negatively impacted the complexity of the offsprings’ brains at birth. In other words, more normal levels of iron were associated with more mature brains at birth. Since meat is rich in iron, this study provides some indirect evidence that meat-eating may be beneficial for the foetal brain. This may be of particular significance for India, which has high prevalence rates of anaemia among pregnant women.
The potential impact of dietary restrictions on the brain and evolution is probably a blip on the radar of the present dispensation. It appears focused on foisting ideology with disregard not only for history and science but even for economics.
Jay Desai is a neurologist. He tweets at @JayDesaiMD.