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The human body wasn't built for modern life

What will the human body look like in the future? I'm not thinking about an already-aging body's appearance 10 years from now. I'm thinking about the differences between the Stone Age depiction of the human body we've carried in our heads since grade school and the human body of tomorrow.

It's the question posed by Harvard biologist Daniel Lieberman in a very readable, often riveting book, "The Story of the Human Body: Evolution, Health and Disease." He addresses the "paradox of greater longevity and chronic disease" reminding us we will live longer but will be much more likely to be diagnosed with a chronic condition that will dramatically affect the quality of those long-lived lives. He thinks we could do something about that.

As illustration, Lieberman reminds us of current reality: "We have conquered or quelled many diseases that used to kill people in droves: smallpox, measles, polio, the plague." People are taller. Formerly life-threatening conditions such as appendicitis or anemia can be easily addressed. Those are good things.

But our additional reality is, as a population, we are obese or on our way to becoming that, and a wave of what must be termed "preventable chronic disease" is sweeping the nation. Lieberman suggests that many of these diseases occur because "our Paleolithic bodies have not adequately adapted to the kind of environments in which we now live." Examples might be acid reflux, anxiety, asthma, high blood pressure and lower-back pain. But the list is much longer.

One of the big culprits in all this appears to be sugar.

"We evolved to crave sweet foods," he says. Our Paleolithic ancestors may have had a little honey occasionally but never had access to such abundant quantities of sugary foods. We don't have the kind of bodies that can cope with all that sugar and the result: we get sick. That reality is complicated by the stressors in life today. There are plenty of them. And here's the deal. The hormone released when something bad happens to us is cortisol; it shoots sugar into our bloodstreams so we can manage that tough, stressful situation with more energy and alertness.

"Whew"— you might be saying, "Got through that." And you probably grab a little comfort food because "stress activates a primal urge to eat calorie-rich foods." This can become viciously circular in an environment full of high stress. And that's not all of it. When you're stressed, you crave those unhealthful foods, eat more of them and consequently have a hard time sleeping, which may elevate your stress even more.

Add to that, our ancestors were a whole lot more active than we are today — lumbering around field and forest to find plant-based foods and hunting meat that was never served with the rich sauces we use today. This topic in even greater detail was featured in a National Public Radio program recently. The story ended up being one of its top-rated offerings and generated lots of feedback. Attention to it is still evolving.

Talk about all this over dinner tonight perhaps? Hold the dessert?

Sharon Johnson is a retired Oregon State University associate professor emeritus. Reach her at Sharon@hmj.com.