It's no secret that I tend to disagree with the mainstream dietary advice we're getting from the government recommendations. I'm clearly in the minority here, but I would attribute that to the fact that the majority of people don't dig deep enough into nutrition to find the truth. The information that makes it to the public eye has become so convoluted, through politics, lobbyists, capitalism, etc, that it's just an incoherent mess. I may go into that conflict of interest on another day, so let's close that can of worms for now.
What I'd like to do, in an attempt to make my view seem a little less crazy, is provide some historical context to the human diet and how we came to where we are today. In my opinion, knowledge of history is vital to understanding any topic of interest. In order to know where you stand, you must know where you came from. I'll begin with a review of hunter-gatherer diets and move through up to the current era, when we began to believe in this high-carb nonsense. So without further delay, here is part one of this historical context series.
For more than 99% of human history, our diets were drastically different than they are today. Before the adoption of agriculture began in approximately 8000 B.C.E., humans hunted and gathered their food, consuming whatever was available to them in their environment. And "whatever was available" definitely did not include grains, legumes, or dairy, although there is some evidence that grains were eaten in emergency situations when there were no other options. The most commonly sited example of hunter-gatherer diets is the example from northeast Africa. According to Loren Cordain and S. Boyd Eaton, two of the leading researchers in paleolithic nutrition, the diet of northeast Africans is likely the ideal human diet because the majority of human history likely took place here; we are in fact nearly 100% genetically identical to these African ancestors. A typical African hunter-gatherer diet would consist of wild meat, vegetables, fruit, nuts, and seeds, clearly a stark contrast between the diets of modern civilization. Note the large meat and fish consumption, which was much higher than ours today. A typical hunter-gatherer would have consumed 55-65% of his calories from meat and fish. Research shows that vegetable and fruit consumption was much higher than in modern diets as well, even the most vegetable-rich modern diets. In terms of macronutrient ratios, African hunter-gatherers would consume 25-30% of calories from protein, 30-35% from carbohydrates, and 40-45% from fat. In contrast, modern Americans consume 15% of calories from protein, 55% from carbohydrates, and 30% from fat.
Once humans migrated out of Africa, approximately 100,000 years ago, they survived and thrived on a variety of diets. Some migrated to similarly warm climates and probably ate a similar diet, but many moved to colder climates where there were far fewer edible plants. In these cases, they relied much more heavily on animals, especially in the winter months. The latest ice age, which spanned from 60,000 years ago to 20,000 years ago, also had a significant impact on human diets, forcing them again to rely on mostly, and sometimes exclusively, animal foods. In these cases, fat must have made up at least 70% of their calories, and probably even more than that. As a general rule, those who settled in colder climates ate more calories from animal products, while those in more tropical climates ate more fruit and vegetables year round.
Clearly, humans were able to adapt and survive eating a wide variety of foods. But none of these groups ate grains, legumes, or dairy as any significant part of their diets until the agricultural revolution, which began around 10,000 years ago. At this time, domestication of animals made dairy foods a possibility, and the ability to grow food made grains (whole grains, mind you) an important part of the human diet. Aside from obvious benefits of agriculture, though, like the ability to feed a larger population, human health took a hit. In fact, there are a surprising number of unfortunate consequences that resulted from the adoption of agriculture, but this post is already too long and I'd rather not explain them. If you're interested, check out Jared Diamond's outstanding article entitled "The Worst Mistake in the History of the Human Race." But the idea that human health declined after the agricultural revolution is not debatable, despite the fact that it is contrary to popular belief today. Humans essentially sacrificed health in order to support a greater population.
In part 2 of this series of blog posts, I'll fast forward to 20th century America and we'll begin to get into modern nutritional science. Stay tuned.