We’re Not The Only Thing Evolving

Photo by: Team Traveller

High fructose corn syrup is evil, we should eat sugar. No, all sugar is evil, we shouldn’t eat any of it. No, raw fruits and honey are good, and agave nectar is better. All clear?

There’s a lot of debate on the Internet lately about fructose vs. sucrose, and whether it makes a difference or not. It usually starts with a claim about high fructose corn syrup, then moves into some technical discussion of how the body processes the different kinds of sugars.

Inevitably someone will suggest that since man didn’t have access to refined sugar until relatively recently — in evolutionary terms — that we aren’t adapted to it. Or more specifically, that we’re adapted to sucrose but not to fructose. Or vice versa, depending on who’s making the point.

You know what inevitably doesn’t come up in these arguments? The fact that our food is evolving, too. And it seems to do it faster than we do.

Remember Michael Pollan?

You can’t read about food today and not know about Pollan, the author of The Omnivore’s Dilemma, In Defense of Food: An Eater’s Manifesto, and most recently Food Rules: An Eater’s Manual. But before those, he wrote The Botany of Desire: A Plant’s-Eye View of the World.

This one isn’t as well known. It produces more a sense of “Huh, that’s interesting,” instead of the “Oh my God, I have to change the way I eat!” that you get from his more recent works. (If you don’t have the time to read it, the DVD is great.) The basic idea is that the plants we cultivate — potatoes, apples, tulips, marijuana — are using us just as much as we are using them.

He isn’t suggesting that plants have intent, but being attractive to humans is a huge survival advantage. If we like a plant, we protect it, feed it, and most importantly, we improve it. Marijuana in particular has changed so much in the last 30 years that it’s almost not recognizable as the same plant that fueled the counterculture revolution of the 1960s.

Wasn’t this supposed to be about sugar?

Were coming to that part. But first there was the question Pollan addressed about marijuana. The active ingredient, THC, binds to receptors in the human brain affecting memory and perception. Scientists couldn’t understand why we would have evolved a sensitivity to a compound that is that specific, and doesn’t seem to offer any advantage to our survival.

They finally figured out that we need to forget. If you remembered every face you saw on the subway, every sad emotion you ever felt, everything you ever experienced, it would be overwhelming. There is a chemical in our brain that helps us forget the things we don’t need. This discovery has led to advances in post traumatic stress treatments and other areas.

The point is, we didn’t evolve a sensitivity to a psychoactive plant. The plant evolved a chemical that humans like.

Starting to see how this is about sugar?

The whole argument over whether we evolved to eat sugar is missing the point. Sugar — sucrose, fructose, glucose … fruits, honey, cane … natural, refined — is not something that exists in one unchanging form that we either evolve to eat or not. Sources of sugar change in response to what we want.

The body didn’t evolve the craving for fruit because fruit ripens once a year and we have to eat all of it while it’s available. (See here or here for how this argument looks.) Rather, the fruit-producing plants evolved to produce something that humans like. The plant doesn’t care if the human dies from diabetes in 30 years, so long as its seeds get spread before next year.

I’d like to wrap this up with a nice, tidy recommendation for how we should eat. But we haven’t had the right conversation yet. As long as we’re talking about what humans evolved to do, we’re not asking what need the sugars evolved to fulfill. The plants know something about what we like: We like sweet. But why?

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