“But that’s so extreme!”
This is a common response when people first hear about the paleolithic diet, which eliminates commonly eaten foods like grains, legumes, sugar and industrial seed oils.
But while a paleo diet may seem extreme from our modern perspective, it’s actually the most “normal” diet for humans to eat.
After the Homo genus evolved 2.4 million years ago, humans lived for 84,000 generations as hunter-gatherers. We ate meat, fish, nuts and seeds, vegetables, some wild fruits when available and starchy tubers like sweet potato and yams.
Agriculture, and the mass consumption of cereal grains it enabled, didn’t happen until just 350 generations ago. And modern, refined foods like high-fructose corn syrup and industrial seed oils – which now comprise up to 30% of calories in the Standard American Diet – have only been around for about three generations.
Another way to look at it is to consider human history as a football field 100 yards long. If you started walking from one end zone toward the other, the first 99.5 yards would represent the amount of time we lived as hunter gatherers. Agriculture, and things like bread and pasta, only showed up in that last one-half yard. Coca-cola, Cheetos, energy bars and other processed foods didn’t become available until the last few inches of that final half-yard.
When you look at it this way, the diet we call “normal” today is what seems extreme and abnormal. There’s no doubt that a lot has changed for us in the past 120,000 years. Our life today would be unrecognizable to our paleolithic ancestors. But there’s one thing that hasn’t changed much over that period: our genes.
120,000 years seems like an eternity to us, but it’s almost inconsequential on the scale of evolutionary time. This means that humans are still genetically wired to live a hunter-gatherer lifestyle, and eat the same foods our paleo ancestors ate way back when.
It also means that if we stray from this evolutionary template, we’ll have problems. All animals evolved to eat a certain way. Cows are herbivores. They have small stomachs and very large intestines, which help them digest the cereal grasses they eat. Cats, on the other hand, are carnivores. They have large stomachs, to help them digest meat, but relatively small intestines because they don’t eat any vegetable matter.
If you feed a cow a meat-based diet, it will get sick, just as a cat will if you feed it grains and vegetables. Likewise, humans get sick when we eat a diet full of foods that we’re not adapted to eat.
There’s a big difference between what’s common, and what’s normal. The Standard American Diet may be what’s common for us today, but it’s far from normal. A normal diet is the one our ancestors ate for a couple million years before agriculture was invented. And it’s the diet we thrive on.