One of the behaviors I cultivated to help me lose weight was the obsessive reading of diet books, looking for new potentially helpful behaviors to try. The latest is Gary Taubes's Good Calories, Bad Calories, and it is a doozy.
This book digs very heavily into the research that challenges the low-fat diets and recommends low-carbohydrate (or at least restricted-carbohydrate) regimens, and it is unusually heavy on the biochemical details. I have a scientific but not biological background, and I thought Taubes did a fantastic job explaining some complicated and subtle stuff.
For example, there is a chapter in which he explains that, while it is simply and mathematically true that storage of energy = calories in - calories out, this does not mean we should assume that "overeating and/or inactivity causes weight gain." It could instead be true that "weight gain causes overeating and/or inactivity" or into "some other thing causes weight gain, overeating, and inactivity." I was skeptical when I read this -- Occam's razor seems to recommend the first hypothesis, you know? But a presentation of the evidence convinced me, if not that the other hypotheses are certainly true, that they are not unreasonable or overcomplicated, that they are worthy of study, and that they do a better job of explaining the clinical evidence than does the simpler one.
I'll do my best to sum it up in the next few paragraphs. The extremely simple version of the hypothesis is that, leaving aside social pressures unique to humans and varying across cultures, which Taubes doesn't really cover, elevated insulin drives all three terms in the equation.
- Insulin drives overeating: high insulin levels in the blood stimulate hunger, suppress satiety (which is its own set of signals, not the absence of hunger), and stimulate cravings for carbohydrates (which are not the same thing as hunger and are sometimes called "emotional eating.") All of these things drive people to eat, certain foods in particular; and some individuals experience severe suffering when they cannot or will not satisfy those drives.
- Insulin drives inactivity: high insulin levels in the blood induce fatigue, apathy, and sometimes depression -- except after a meal when there is plenty of blood sugar around. (Add to that humans' ability to learn from experience and you get another feedback loop that drives eating: I feel depressed, sluggish, and anxious, and I know if I have some carbs I'll feel better instantly.)
-And insulin drives fat storage: It stimulates muscle cells to burn sugar instead of fat. it speeds up the chemical cascade that splits blood triglycerides into fatty acids that fat cells can absorb and that links them back up into triglycerides that fat cells can hold onto, while it slows the opposite cascade that splits up fat-cell triglycerides into fatty acids that can escape into the blood to be carried to cells for burning.
(That bit about speeding up and slowing down the rates of opposing processes is an insight that helps me, as an engineer, adjust my mental model of metabolism: There are more unit operations, and more rates to keep track of, than I realized. We're all used to thinking of the fat in our fat cells as a long-term store, mobilized only in the event of prolonged hunger. But radioactive tagging studies seem to show that the fat in our gut, blood, and fat cells mixes and moves about constantly. Our bodies burn glucose sometimes and fat other times, and it changes on a minute by minute basis, all orchestrated by insulin.)
Recall that I've been thinking of myself as a recovering glutton. As I read through the book, I felt a little bit disturbed. Taubes is obviously interested in showing that gluttony isn't the cause of obesity, that biochemistry drives people both to gain weight and to feel hungry, to crave and to eat. He even presents some evidence (from rat studies) that in some cases it's not even possible to lose fat by eating ZERO calories -- obese rats with certain metabolic conditions will die of starvation, if you take away their food, before they can lose much of their fat. Is he trying to excuse people from the idea that their behavior matters? Does willpower play NO role at all? Is there no hope that the opposite of gluttony -- the virtues of temperance, fortitude, and self-control -- can reverse the problem?
I felt that the very last chapter, on hunger and satiety, resolved some of that question. The resolution comes in thinking of hyperinsulinemia (background high levels of insulin) as a state of physical addiction. It's a bad feedback loop: easily digested carbohydrates raise the background level of insulin and blunt the cells' response to it, while the high insulin level creates hunger and a craving for easily digested carbohydrates, plus suffering when the craving is resisted.
Addictions are hard to break, and sometimes you get addicted through no fault or no conscious fault of your own. Willpower and hard work is sometimes not enough to break an addiction; compassion and outside help go a long way. And yet... addictions CAN be broken through hard work, through the voluntary acceptance of suffering, through decisions of the will to forgo temporary comforts. We are human, and we are able to use our intellect and our will to decide how to respond to the signals our body sends us. With good information and enough strength from inside or outside, we can make good choices even in the face of apparently intolerable pressures to make bad ones.
There were two things in this book that particularly resonated with my experience.
First was the diet prescribed by Margaret Ohlson, whose female patients achieved remarkably successful weight loss (about two pounds a week, if I remember right) with moderately restricted calories and moderately restricted carbohydrates. Those patients were eating 1400-1500 calories a day, of which about half the calories were from fat, a quarter were from protein, and a quarter were from carbohydrates. The reason this resonates with me is that this is pretty much what I happened to be eating during my weight loss. The only thing I was trying to control was calories, but I measured and recorded fat/protein/carbs too. I ate what I felt like eating, controlling only the total calories, and apparently I felt like eating 50% fat, 25% carbs, 25% protein.
I guess that's technically a low-carb diet. Did I give the impression I had abandoned low-carbing? I wasn't trying to eat low carb, in fact I felt that I was enjoying plenty of carbs, and maybe I gave the impression that I had abandoned the low-carb thing; but understand that over the years my perception of an appropriate amount of carbs has dropped considerably, and when I "freely" consume bread or pasta or rice I still don't tend to eat more than a few servings a day.
Here's the second thing that resonated with my experience. In the last chapter, Taubes quotes a clinician who successfully worked with obese children. That clinician observed that in his patients the craving for sweets and easy-to-digest starches -- though not the intolerable hunger -- persisted for a year to eighteen months while the patients followed a diet that restricted their carbohydrates. But at some point, the cravings ceased, apparently quite abruptly. He said that his patients could identify the one- or two-week period when their cravings ceased. Their background insulin level, itself stimulated by a background level of constant carb-nibbling, had slowly healed itself and dropped to normal.
The day I woke up and said I was ready to try being hungry was May 13, 2008. Mary Jane was twenty-one months old. I had been trying, with what felt like no success at all, to stick to a truly low-carb diet since a few months after she was born.
So. Maybe the reason I was successful "this time" was all that long, hard work with nothing to show for it that preceded it. I wasn't losing weight, but maybe -- maybe -- I was slowly healing inside. Maybe May 13 was the day I was first cured. With no addiction and no bad feedback loop, and a reasonably healthy and moderate diet, it became... not all that tough.
I feel better about this possibility. You'd think I'd feel better if I could congratulate myself on having finally developed the virtues of fortitude and self-control, but really, I know myself, and I know that I am not any more virtuous than I ever have been. Still, I also know that I worked hard for a long time, and that I worked hard against something that was truly difficult. But it feels more correct to say that the hard part of the work perhaps ENDED, not BEGAN, the day I began to lose weight.