I took biology during my freshman year of high school. The class came right after lunch, and I struggled to stay awake. It should have been easy. Our teacher, Mr. Otto, was a rock star. He had studied gorillas in Africa (Lesotho), rocked a pony tail (and pulled it off), and was just one of those cool teachers. But day after day, I'd nod off in class. I just accepted it as normal -- people get sleepy after lunch. No different than people getting sleepy at night.
It didn't help that I couldn't see the blackboard. It was a large, lab-style classroom and I sat near the back. As I would squint at the board trying to take notes, I thought, "Huh, it's a little odd that they would build a classroom so long that you couldn't see the blackboard from the back." As if the classroom were defective, not my eyes. (My delusions of grandeur started at a young age.) I asked the girl sitting next to me if she could see the blackboard. She said no, it's fuzzy for me too. So we both continued squinting, confirming each other's belief that we each had normal eyesight. Turns out, of course, that both of us needed glasses.
The moral is simple. Don't define "normal" by looking at the people around you. We understand this concept in the case of the girl with bad eyesight sitting next to me in class, but we forget it elsewhere. We think that if everybody in our family has bad eyesight, then it's normal to have bad eyesight. Or if everybody in the country is overweight, then it's normal to be overweight. Or if all the kids in class fall asleep after lunch, then it's normal to be tired after eating.
But when you widen your frame of reference to include other people (like other cultures) and periods of time (like our hunter-gatherer ancestors), you see normal in a whole new light. The body's natural condition is to be healthy. That is normal. And to be overweight is abnormal, to have acne is abnormal, to have flat feet is abnormal, to have allergies is abnormal, to get sick every month is abnormal, to fall asleep after every meal is abnormal, to be weak is abnormal, to be depressed is abnormal, to be unhealthy is abnormal.
Well, it's time to take back normal. Healthy is the new normal.