INTERVIEWER What happened when you met with the [UC Berkeley School of Public Health] epidemiology students?
TAUBES Again, it was a little discouraging, only because these kids really want to do good, they want to make a difference in the world. Thatâ€™s why they go into the field. They want to have an effect. But as I say at the end of the book, to do science right, your primary motivation has to be to learn the truth, and if youâ€™re infected with this desire to change the world, to save lives, it takes you away from the fundamental motivation, which is to get it right. If you want to save lives, then you want to get the word out as quickly as possible. You don’t want to wait ten or twenty years or more for definitive evidence, for the rigorous tests to be done; you want to give advice and tell people what you’ve learned, even if you only think that you’ve learned it. Doing science right takes a long time. So does good journalism. You can say the difference between my book and Gina Kolata’s book is — not counting whatever difference in intellect we begin with– my book took five years, more than full time, because I wasnâ€™t going to say anything until I was certain that what I was saying was sound. She wrote her book in two years, part-time, while still working full-time as a New York Times reporter.
INTERVIEWER Yeah, theyâ€™re very different.
TAUBES Even when I was writing magazine articles, if I was in danger of missing a deadline, which was often the case, I would ask my editors, â€œDo you want it on time, or do you want it right?â€.
INTERVIEWER There was a managing editor at The New Yorker, one of the first, whose motto was â€œDonâ€™t get it right, get it written.”
TAUBES When I was a young journalist working for Discover, which was owned by Time, Inc., the philosophy was that one of the worst things anybody could do was over-report a story. Just get the facts and get it out. Except science doesnâ€™t work like that. Science, youâ€™ve got to get it right, and that takes time, and you canâ€™t do it on deadline. Along those lines, I did read one of your blog entries about settling points versus set points, and I thought it might beâ€¦ You know, I Google myself, as all writers do fairly regularly, so first you read all news stories that day, hoping that the Google Alert might have missed something, and then you go to the blogs.
INTERVIEWER So you read my post about the most surprising thing in your book?
TAUBES What was the most surprising thing?
INTERVIEWER That you didnâ€™t agree that set points play a role in homeostasis.
TAUBES Itâ€™s funny â€“ the more I think about it, the more Claude Bernard was brilliant. (I’d like to do a book on Claude Bernard, but probably can’t because my French is terrible.) In particular, this idea of the milieu interieur? The fundamental idea of homeostasis is that the body works to maintain the stability of what he called the milieu interieur, which gets translated to â€œinternal environmentâ€. What he meant by that is the conditions right outside the membrane of the cell, every cell in the body. So the body wants to maintain stable this internal environment — the pH, the blood pressure, the ionic potential, everything — of the cell itself. So it wants to make sure that the environment the cell lives in — every cell — remains relatively stable. in that sense, we’re this huge symbiotic organism made up of billions of individual cells, and homeostasis functions to keep the conditions that these cell live in stable. So each cell lives in this little isolated world, and itâ€™s got to see stable conditions, or itâ€™s going to die. The idea of the set point is that thereâ€™s some central controller in the brain that maintains homeostasis, but that’s naive. Rather, there’s an unbelievably complicated mechanism composed of individual settling points. Like the fatty acid concentration on the interior, and exterior of the fat cell. If thereâ€™s more fatty acids on the outside of the cell membrane than the inside, then fatty acids flow into the cell, and you get slightly fatter. Thereâ€™s no brain in charge. The brain may respond, and the hypothalamus sends signals back and forth, and effects changes in hormones in response to changes in the environment, but thereâ€™s so many different interrelated, interconnected feedback loops involved that to refer to a set point is to grossly oversimplify things this beautiful homeostatic system, and it directs attention away from the body, where all these feedback loops interact, to the brain. Did you ever read any books on chaos theory?
INTERVIEWER No, I havenâ€™t.
TAUBES Well, to understand homeostasis you have to understand this concept of dynamic equilibrium, where there can be hundreds of forces acting simultaneously. And the point is, youâ€™ve got these negative feedback loops all over the body, and they involve the brain, but on some level, the dynamic equilibrium youâ€™re looking at is right at the cellular level. Thatâ€™s where the forces converge to make us leaner or fatter. And the brain is part of these loops, but to concentrate on the brain misses the big picture.
INTERVIEWER The brain is sensitive to the environment — sure, the set point doesnâ€™t really exist anywhere, and sure itâ€™s a function of about a zillion things, not all of them in the brain, sure. But the reason I like that idea of a setpoint is that itâ€™s easy to imagine something going up and down, rather than a million things going up and down.
TAUBES But the problem is once you oversimplify, there’s a tendency to believe the oversimplification. You should go back and read the papers on settling points. There were a couple, if I remember correctly, written by psychologists from the University of Chicago. You should go back and read those original papers. Theyâ€™re fascinating, and the point they make, is that you donâ€™t need the brain involved. Like we donâ€™t think of the brain regulating blood pressure. You donâ€™t really think of your brain regulating blood glucose. Those cycles I described in my lecture, you know, the triglyceride fatty acid cycle and the Randall cycle, serve to regulate blood sugar. Then hormones are layered on top of those cycles, and the hormones are determined, in part, by the hypothalamus, so you get the brain involved, and the sensing of the environment, but there are other ways to sense the environment, like temperature sensing of the skin, evaporation. There are other ways that we adjust to the environment without the involvement of the brain. One of the things I left out of the book, for instance, is this theory that hunger is perceived by the liver.
INTERVIEWER Perceived, or controlled?
TAUBES Perceived. Or sensed by the liver. You know, your eyes collect photons, and then they send the signal back through the optic nerve. The perception of the universe is done in the inside of the brain, but the eyes are the sense organ that collect the photons. Your ears detect sound waves, but your perception of what youâ€™re hearing is inside of the brain. This theory says that your liver senses fuel availability and then your brain integrates the signals from the liver and registers them as hunger or the absence of hunger.
INTERVIEWER Hunger is internal. Itâ€™s like the recognition. Hunger is not something external to the body.
TAUBES Let me re-phrase it. It senses fuel ability. Then your brain perceives it as hunger and initiates — that would be a better way of putting it. But the sense organ of fuel availability is your liver. I had some discussions with Mark Friedman, a fascinating guy, really smart. Heâ€™s at the Monell Institute.