A friend informed me that he had lost about 30 pounds over the last year on the Paleo Diet, and felt better than ever. I did a bit of research and the concept seemed appealing. Apparently, human ancestors had a fairly homogenous diet for millions of years in the Paleolithic Era, until about 10,000 years ago when humans became civilized and started farming. Our diet now is radically different from what it was during the Paleolithic Era.
The logic behind the Paleo Diet -- and I'm a big fan of logic -- is that it seems reasonable to expect that our bodies had time, over the course of the millions of years in the Paleolithic Era, to evolve such that we became biologically optimized for that diet. The subsequent 10,000 is the blink of an eye, in evolutionary terms, so it stands to reason that we have not significantly evolved over that time to optimize our bodies for our present type of diet.
The Paleo Diet generally consists of av0iding grains, grain-based oils, processed sugars, processed foods, and salt. And trying to eat meat that is not grain fed. Well, there are different versions of it. The net result is rather similar to the Atkin diet, IMHO.
Though I find the concept appealing, I see at least three flaws in it.
First, it places personal health above global sustainability. Even assuming the Paleo Diet is needed for a person to achieve optimal health, is it possible for our planet to generate enough non-grain foods to feed a population that is over 6 billion strong and growing? Particularly if you want to insist that the animals we eat are not grain fed? Without doing the math (I'm more of a "big picture" debater), I am fairly confident in saying it would take the resources of multiple planets to allow everyone to embrace this diet.
In fact, I'm pretty sure it is the population increase that prompted humans to embrace an agrarian and largely grain-based lifestyle and diet 10,000 years ago. It seems rather naive to think that after our population has grown immensely, we could then abruptly switch gears and return to the kind of diet that seems premised on the notion that, for optimal health, we all need a hunting range full of juicy animals at our disposal.
I imagine a Paleo eater might respond, "Oh, I did not mean for everyone to eat this diet, just me and whoever else wants to be healthy..." First, I'm pretty sure everyone wants to be healthy (healthier, in fact). I'm also concerned about embracing a diet we agree must be limited, by natural resources and economic realities, to a fraction of the populace. It seems very...elitist. Okay, Ayn Rand would be proud, but I'm not quite so cut-throat.
I think a better approach would be to create one's personal diet based on a balancing of various factors including not just one's own optimal health, but also global sustainability. It's not as if everyone who fails to follow a Paleo Diet sinks into a morass of disease and dysfunction. (Along those lines -- though somewhat off-topic -- I do believe it is a moral imperative to try to maintain one's own health due to the cost and scarcity of medical resources on the planet. Thus, I'm not suggesting we eat whatever is most sustainable no matter how unhealthy it may be.)
On to my second issue with this diet: It is a blatant step backwards. Hell, this is the whole point. It's right there in the name. Are we to go back to living average life spans of 35 years, too? To put it another way, the underlying logic -- that 10,000 years is not enough time for our bodies to evolve to become optimized to a new diet, as compared to the millions of years our ancestors ate the Paleo Diet -- necessarily assumes that if we stick with our grain-heavy (and dairy heavy,, and even processed food-heavy) diet for a few millions years, our bodies WILL evolve so that our descendants' bodies achieve optimal health based on whatever diet we are following, so long as we stick with it.
I mean, by the reasoning of the Paleo Dieters, what if you were at the dawn of the Paleolithic Era, 10,000 years into it, when human ancestors had just begun to live and eat a Paleo Diet... Could you go to them and say, "No, your bodies aren't evolved to optimize lean meet and vegetables...go back to eating grubs and roots [or whatever]..."
Evolution is not a force that exists outside of us, but is largely a product of OUR OWN CHOICES. If we all CHOOSE to follow a Paleo Diet, we then have DECIDED that we will not allow our bodies to evolve in a manner that optimizes any other diet. On the other hand, if we CHOOSE to follow a different diet, then the very reasoning underlying the Paleo Diet indicates our bodies will adapt to it so that it becomes our optimal diet. Sure, this may not happen in our lifetime, or in 100 lifetimes, but it is as inevitable. As inevitable as evolution.
Pretty much any life coach will tell you one of the most important, if not the most important, tool to get a person's life on track is a plan, a goal. Otherwise, people simple drift along, following the path of least resistance, which rarely leads where they want to go. Funny, how everyone nods and says, "Yes, that makes sense," when you are talking about a person, but they don't apply the same reasoning to our species. Humanity needs a plan. Not just af 5 year plan, but a 500 year plan. Maybe a 50,000 year plan.
Eating a particular diet simply because it's what pre-historic cavemen ate such that evolutionary forces may have optimized it for our bodies, is abdicating personal responsiblity for effecting a biological and evolutionary change.
My third issue is more nit-picky. I have no evidence that evolution necessarily would have caused our bodies to evolve such that the Paleo Diet was optimal. In evolutionary terms, consider a particular characteristic as an axis on a graph. Evolution may cause significant movement along that axis, over time, if that particular characteristic is a significant predictor for survival or procreation. Animals, plants and humans have many characteristics that may be largely irrelevant in terms of these issues, so we see no evolutionary push one way or the other as to these characteristics. Did one's ability to thrive on a Paleo Diet a SIGNIFICANTLY improve one's rate of survival or procreation compared to others from the same era? Maybe, or maybe not.
From what I read, food was scarce during that time period, and one's ability to survive and perform without food (i.e., fasting ability) was likely more significant for increasing one's chance of survival and procreation. So humans probably evolved to be able to fast longer and longer time periods during the Paleolithic Era. That axis could have largely swallowed any other diet-related axis.
And even assuming the extent to which one's body was optimized for the Paleo Diet was a significant evolutionary axis, that would only establish that people at the beginning of the Paleolithic Era would do worse on a Paleo Diet than those at the end of the era. It in no way establishes that these people would do worse on any other diet.
So, to summarize my third point, on further reflection, I find the logical underpinnings of the Paleo Diet to be seriously flawed. I think the health benefits and weight loss experienced by those who stick to this diet is probably more a product of reduced overeating, being more mindful of what one eats, reducing sugars and fatty oils and processed foods, and other healthy changes that could have been made while still eating grains and otherwise embracing a diet that is more ethical and sustainable for the species and planet.