Why We Get Fat

I just posted a video about why we get fat. It results from cravings for high-calorie foods. These cravings were given to us by natural selection. They were an essential part of survival back in cave man days. Cravings made us eat every bit of food we could find. Our bodies then stored excess calories in the form of body fat. We would feast on food when it was briefly available, then live off of the stored calories in our body fat during times when food was not available—times of deprivation or famine.

Body fat is the safest way for us to store calories. The calories are safe from pests and mildew. And body fat has advantages other than just storing calories, which is its main function in natural selection. Visible accumulations of fat can make sexual characteristics more noticeable, and thus be favored by sexual selection as well. Also, since we walk upright on two legs, we also sit upright, and it is very nice to have a fat butt to sit on.

But today, our bodies are storing calories for a famine that never comes. There are more obese people than hungry people in the world today. Today, for our health, we have to deliberately do things for which our caveman ancestors had no choice. We must limit our calorie intake, and make sure many of those calories are in healthy food—that is, just about the only kinds of foods available to our evolutionary ancestors. We also need to make sure we get plenty of exercise, something our evolutionary ancestors had no choice about.

This is just one example of many in which modern medical problems are best understood in the light of our evolutionary history.

Vanishing Utopias

We all know that utopias cannot ever exist. But, according to historian Yuval Noah Harari, author of Sapiens: A Brief History of Humankind, we keep getting closer to it. In fact, our approach to it is accelerating.

It is a long book, almost 500 pages, but it covers the entirety of human prehistory and history, up until the present day, which for the author was 2014. You will not find lists of empires and dates. In this way, it is almost the exact opposite of what is still perhaps the most famous overview of world history, the Outline of History by H. G. Wells.

Instead, the author seeks general trends and explanations for everything that has happened. Here is an example. Why did human evolution seem to proceed so slowly before the arrival of modern humans? For example, Homo ergaster stone tools in Africa remained unchanged for a million years. Harari says that all other animal species, and all humans before Homo sapiens, have or had a biological constraint on their ability to think of new ways of living. Before the human lineage could make any progress, we needed an innovation, invisible in bones and DNA, which allowed us to imagine the future. Neanderthals, for example, he said, did not have “the ability to compose fiction.”

But the author suffers from the delusion of technological optimism, which is very common among writers of popular sociology. Here are two examples which considerably erode the credibility of the conclusion of the book.

First, he seems to assume we will never run out of energy. This is because we invest some of the profits from the old kinds of energy into developing new ones. This has, in fact, happened. One obvious example is that England was running out of wood, so they invested money and research into using coal, which required the invention of the steam engine. Before modern times, all energy was either from burning wood or from human and animal muscle power. Medieval people did not even imagine steam, hydroelectric, or atomic power.

But this will happen only if we deliberately invest in new technology. Right now we need to invest in green technologies such as wind and solar energy. We have done so, but powerful ideological and political forces oppose the adoption of green technology. Donald Trump has made it very clear that his solution to our future energy needs is to pump more oil. Technology will not save us, because Trump will lead us boldly into the twentieth century.

Harari also speculated that wars were becoming rare. It is true that there were fewer wars in 2014 than there had ever been in the past. This was easy to believe in the balmy days of the Obama administration. But almost as soon as Harari’s book was published, Putin decided to invade the Ukraine, for reasons that are not clear even to his supporters, who do not dare to have an independent opinion; and Harari’s own country, Israel, is waging what many observers claim to be a war of extermination against the Palestinians.

Harari even speculated about how to be happy. Happiness is, he said, the product of serotonin levels in the brain. No matter what your external circumstances happen to be, no matter if you are in pain or slavery, you will be happy if you have a lot of serotonin. I think this opinion is a product of the author’s scarcely-hidden admiration for Buddhism. And, he implies, serotonin levels are not only biologically determined—you are either a happy or a depressed person—but also remain unchanged during your life. But this is true only for people who are clinically depressed. They need more serotonin but I do not. Also, I am certain that I am happier now, having completed so many of my life goals, than I was back when I had no idea if my future would be successful.

We need to admit that lots of things are getting better—the same message as Steven Pinker’s Better Angels of Our Nature—but that we still have a lot of work to do and our success is not assured.

We all live in imagined realities. Despite the absence of evidence for spiritual realities, we will be individually unhappy and collective failures if we live in the way the apostle Paul described in one of his epistles: Eat, drink, for tomorrow we die. We have to at least imagine that we can make the world better.

How I Became a Scientist

I became a scientist one evening in 1978 when I was participating in the plant ecology group studies seminar at the University of California at Santa Barbara. I asked a stupid question.

I was an undergraduate environmental biology major. I took some very good courses that acquainted me (firsthand, with extensive field trips) with the ecology and vegetation of southern California. I continue, over forty years later, to draw from the wellspring of the inspiration I got at that time for my writing.

If I just wanted to write, and to teach at perhaps a community college level, all these experiences would have been enough. But I wanted to be a university professor. For this, I needed to learn how to do my own research. If I had just wanted to help a researcher, I could have become a lab technician. But I wanted my own research to expand our understanding of nature.

When we got back our graded exams in Bill Schlesinger’s plant ecology class in 1977, I got an 88, which seemed kind of mediocre to me, but it turned out to be the best grade in the class. Bill invited me to participate in the plant ecology group studies seminar, which met once a week in the evenings. These were the meetings in which the graduate students presented their own research, leading to advanced degrees. I assumed I was up to the challenge of participating in this.

The instructors (all of the botanists at UC Santa Barbara) assured me that the first quarter of this course all I had to do was participate intelligently in discussions. In many cases, we read a paper published in a scientific journal and discussed it. I, however, struggled to understand the papers. Anyone who has, without training, looked at a scientific paper knows that scientific research is a world unto itself. I read the papers as carefully as I could and wrote down questions that seemed intelligent to me. But I was unable to launch myself into a discussion that was at the level of some of the best researchers in the world.

That is, until one of the faculty said, “I want to hear from the new people.” I was the only new person there. Bruce Mahall looked and sounded like a fierce Scottish warrior.

Fortunately, I had a question ready. The paper was about air pollution infiltrating into the soils of a forest. My question was, “What is the oxygen layer?”

Everyone in the room was stumped. They didn’t know what an oxygen layer was either.

Finally one of the younger faculty piped up, “Oh, he’s talking about the O₂ (oh-two) layer.” O₂ is the chemical formula of atmospheric oxygen. Each molecule consists of two oxygen atoms. I knew this from the year of general chemistry, and another year of organic chemistry, that I had been required to take from 1975 to 1977. But apparently, as it turns out, O₂ also refers to the second organic layer in the soil. The two organic layers, the second of which is sticky humus, sits on top of the mineral soil layers. I think the young professor was gloating a little, as young professors at big research universities often do. They have to prove themselves by outshining others, even if the others are little undergrads. No harm done, though. I had asked my question and was now a participant, rather than just an observer.

This was the evening I became a scientist. My first act as a scientist was to ask a stupid question. But, in a way, the entire history of science is about people asking stupid questions and then pursuing the answers. For example, it is obvious to us today that the Earth revolves around the Sun, but in Galileo’s time, it was not obvious. Other scholars were openly hostile to Galileo. Go outside and look. You cannot see the Earth going around the Sun; you have to figure it out from evidence. This would not be the last stupid question I would ask myself or others.

A student could take the evening seminar course as many times as necessary, because the course was never twice the same. The second time I took the course, I had to sign up for leading one of the discussions. We sat at tables around a central point. The signup sheet started on the other side from me. By the time the sheet got to me, there were two slots left: the next week, and the week after. Bill Schlesinger was my undergrad advisor and he signed up for the first slot. I “chose” the second. I had no idea how to get started, so Bill offered to show me how.

When I went to his office, he said, “If I were you, I’d be pretty scared right now.”

I think he was only half serious, since all the faculty and graduate students knew to not judge me by their standards. Bill’s advice was pretty simple. Choose a paper (within the topic the group had chosen), and then also read the papers in the reference list at the end. Put them all together, and you have a presentation.

The next week I gave my presentation, something about nitrogen in grasslands. It was apparently pretty good for an undergraduate. Some faculty told me so. Cornelius H. Muller (“Neil”), however, did not say anything. He was a very old and experienced plant ecology researcher, from back in the 1930s when to do research all you had to do was ride your horse around. By riding his horse around, he had discovered the complex mixture of oak species that lived on hilltops over the Texas desert. (He spoke with a Texas accent.) This was an important breakthrough in our ecological understanding, because the oak woodlands of these “sky islands” were little remnants of what had once been extensive oak forests, which died out as the weather became dry in recent millennia, except for the hilltop survivors. He discovered several species that had almost become extinct. As an elder statesman in ecology, he always wore a tweed jacket, white shirt, and red bowtie. He came up to me after my presentation. Though he said nothing, he had a tin of cookies, and offered me one, with a smile. I think this meant he was pleased.

The next summer, 1978, I was as ready for my own research as an undergraduate was likely to be. Bill Schlesinger oversaw the research project. I remain amazed at how a well-known and rapidly rising star of plant ecology took time for what turned out to be a research project that was big on experience and short on success. I had access to all of this grant-funded research equipment. Short on success, but experience was what I needed.

I chose to analyze the patterns of which plants grew where in an area of the Santa Ynez Mountains upslope from Lompoc, California. In some places, there were chaparral shrubs, that needed fire to persist; sage scrub bushes, that did not; and some very interesting pine trees. These bishop pine trees were a little population over a hundred miles away from its main habitat. This little area was also unique because it did not have what we would normally call soil. The ground consisted of a thick layer of diatomaceous earth. It had formed when dead diatoms (floating single-celled algae) had built up in shallow oceans, such as the Pacific coast that was only a few miles away, over the course of millions of years. The diatoms became rock. Geologic forces (such as earthquakes with which California is all too familiar) raised these rock layers, bright white, up a few hundred feet. Here, and only here, was where the bishop pines grew. Why? Nobody really knew. Here was my chance to not only get experience but to advance the scientific understanding of nature.

The diatomite is not really rock, and is very lightweight, as you can see from this 1978 photo of me.

We quite reasonably assumed that the pines grew on the diatomaceous earth because of the chemical composition of the earth, which was different from the soil of the surrounding hills. My project was to estimate the importance of the different kinds of plant cover (pines, chaparral, etc.) and to get soil samples. We would, quite simply, see if the pines grew where they did because of the chemistry of the soil samples.

Here is where the experience came in. Crawling through a chaparral is difficult and dangerous. Little branches almost completely fill the space. I was not a large person but even I had trouble getting around in the chaparral. Rattlesnakes, which were abundant, could get around in it better than I could. I also took wood core samples from the pine trees. It was very hot. If I could do this project, out in an almost brutal natural setting, then the life of a field researcher was for me. I was on my way to eventually becoming a professor. You don’t get there by sitting in a library.

But it was not the only experience I had along the way to becoming a researcher. We analyzed the major soil nutrients in Bill’s lab, which was one of the best places to do so. When we compared the nutrient makeup with the vegetation cover, we found that the pine forests had more magnesium in the soil than the other types of plant cover. This might mean that pines grow best on high-magnesium soil. Or not. But there was one puzzling aspect of the results. The diatomaceous earth seemed to be ten percent sodium. When I presented my results at the seminar, we were all puzzled. Bruce pointed out that if the sodium was in the form of sea salt, not unthinkable with the ocean just a mile away, then there would also be ten percent chloride, and the soil would therefore be twenty percent salt. This would not only be enough to kill any plants, even the pickleweeds down in the nearby salt marsh, but it would mean that the soil would dissolve in the rain.

My seminar presentation also turned out to be funny, but not because of the salt. Some of my measurements were from the edges of the Johns Manville quarry, where the company dug away whole hillsides of diatomaceous earth to sell. The man I stayed with in Lompoc was the leader of the little church I attended, and as an employee of JM, he got me permission to work near the mine. At the seminar, I showed a picture of myself that I had taken with a camera on a tripod. I had on a miner’s hard hat on which I had placed two flaps to cover my ears. I explained that this was to keep the flies out of my ears. For some reason I still do not understand, the whole room of professors and students erupted into unaccountably prolonged laughter when I said this.

Later, long after all interest in my research project had passed, Bill realized what had happened. Sodium was one of the components of the solution which we had used to extract nutrients for the analysis. The sodium was not actually in the soil. This seemed like such an obvious blunder that only I could have made it, but an eminent scientist had made it instead. The experience I got from this is that anybody, even a great scientist, can make a silly mistake.