Last October was the last time I weighed myself regularly. I weighed around 170-175 lbs. Since then, I have not counted calories or, really, even stepped on the scale. I have just eaten and drunk whatever I wanted, pretty much whenever I wanted. Spurred by a friend’s LJ post about her dieting efforts, I weighed myself yesterday, just to see what had happened in the last ten months or so. My weight: 172.

I do want to be clear that I’m not bragging or anything like that. I’m not showing off, “hur hur, my metabolism is awesome I can eat whatever I want and not gain weight!” Actually, for many years, my weight hovered around 165-170, pretty much no matter what I did. Once, in a frenzy of effort, I exercised and counted calories to get it down to 155, but… you guessed it… it crept back up to about 165 and stayed there. Until around last October or thereabouts when it went up to around 170-175 and stayed there. So, I have both “failed” at dieting and gained weight before.

So what is my point? If I can go a whole year without counting a single calorie or thinking twice about what goes into my mouth, and at the end be pretty much exactly the same weight that I started out at, what must that say about the power of the metabolic processes that are maintaining my weight? I guarantee you there were days in there where I consumed 4,000 calories. You know, “bought a pint of Ben and Jerry’s then ate the whole thing over pound cake,” kind of days. “Ordered a large pizza then ate all eight slices instead of leaving four for leftovers,” kind of days. Somehow, it all worked out in the end, and I weigh the same as I did a year ago.

The basic premise of dieting is that if you eat fewer calories than your metabolism burns, then you will lose weight. And, strictly speaking, that’s true, but the problem is that it treats the amount your metabolism burns as a fixed number, which it isn’t. Studies have concluded that the body’s metabolism speeds up or slows down in response to increased or decreased calories. The degree to which this happens varies depending on the individual, but in one study, some participants had to consume as much as 10,000 calories a day in order to gain weight, and then quickly lost it without any particular effort once the study ended. These people were certainly outliers, but they were not mutants. Your body and mine probably works the same way, even if the threshold above which our metabolism could not compensate, and we would begin to gain weight, is less than 10,000 calories a day.

If weight gain or loss was as simple as “calories in – base metabolic rate” then the chances of my ending up the same weight after a year of not monitoring my food intake would be nil. Every day for the last year, some part of my biological process has moderated my desire to eat food and my metabolic rate in order to keep my weight where my body “wanted it” to be, without me even being aware of it. Kind of like breathing or blinking my eyes. I don’t think about either of those things very often, but they keep happening. I can take conscious control of them, but it requires a lot of attention and effort, and pretty soon I go back to not thinking about them, which is the way my mind and body normally work.

Counting calories in order to lose weight is like trying to consciously breathe or blink your eyes 20% slower than you normally would. All day. Every day. For the rest of your life. Could you do it? Yes, if you really wanted to. Would you do it? Probably not. You’d be out of breath and dry-eyed all the time, and at some point, you would just say, “fuck it.” And who could blame you? Who wants to be out of breath and dry-eyed all the time? Who wants to be hungry, physically weak, grumpy, and measurably worse at tests of cognition (all effects of dieting) all the time?

The reality is that weight is 70% heritable. That means that weight is more heritable than breast cancer, mental illness, or heart disease. You can do things to influence your probability of getting cancer, mental illness, or heart disease. If you know you are at risk, you can avoid exacerbating factors. But in the end, we all understand that some people are going to get these diseases through no obvious fault of their own. It’s just genetics. This is the same treatment that we should give to weight.

Here is a link to an article with more on this topic.