Our past beliefs affect what we pay attention to, how we prioritize our skepticism, and how we interpret ambiguous evidence. This can create belief basins, where there are multiple sets of beliefs that reinforce each other, appear internally consistent, and make it hard to see the other basins as valid possibilities. On the topic of nutrition, I seem to have found myself in a different basin. I've looked through every nonstandard lens I could find, repeatedly applied skepticism, and firmly committed to not make the same mistakes everyone else is making (as a priority on par with not making mistakes at all). I've arrived at a set of beliefs that, as far as I can tell, is internally consistent, reasonably compelling from the inside, and completely contrary to what most other people in our culture think.

This makes for a difficult writing project. When I try to argue nonstandard positions, many of the arguments are tendrils reaching into other nonstandard positions. I've finally managed to get into a post-every-day cadence; part of the key to that was accepting that sometimes those arguments will be dangling references. Hopefully after a month of this, the whole thing will cohere. If not, well, the fragments are pretty interesting too.

The most-common basin of nutrition theorizing centers on obesity, and on a particular theory of obesity which goes like this. Food, especially modern processed food, tastes good and is appealing. Some people, if they followed their urges, would eat too much or become obese, so they have to exert self control not to. Weight is a function of calorie intake and calorie expenditure ("calories in, calories out"), and expenditure is primarily a function of behavior. So if someone is trying to lose weight, and it isn't working, then they must be having willpower failures and eating more than they intend, or exercising less than they intend.

I currently think there are quite a lot of things wrong with this model, but today, I'd like to focus on one in particular. It's not the only or the most central objection, nor is it a particularly actionable model fragment. But it's an issue that's important to me in particular, and it's one of the wedges that moved into a different belief basin.

I am not obese, and have never set out to lose weight. But sometimes, I have overwhelming cravings for sugar. I would not be able to resist these cravings without great willpower.

If I ever did successfully resist one of those cravings, I would probably die.

I don't mean this figuratively, or in a heart-disease-years-later sort of way. I mean that if I get a powerful craving for sugar, and I don't promptly eat something that has sugar in it, then this will be a life-threatening medical emergency. This is because I have type 1 diabetes, and craving sugar is a symptom of low blood sugar, aka hypoglycemia. What T1 diabetes means, basically, is that I have to micromanage my blood sugar using insulin. Eating carbohydrates raises blood sugar, insulin lowers it, these need to be matched pretty precisely, and the whole thing is somewhat error prone. Too much insulin and blood sugar falls below 70mg/dL, and I get the sugar craving. I've never been below 40mg/dL, but people who do become mentally impaired, then lose consciousness, then die.

Under the usual theory of obesity, craving sugar would mean that I had been hijacked by the superstimulus of processed food, and that willpower was my defense against this hijacking. But actually, in this case, the craving is a safety mechanism. Sugar craving is to dangerous hypoglycemia as thirst is to dehydration.

With that example in mind, I started thinking about the double-digit percentage of people who drop out of weight-loss studies. And the much-larger percentage of people who start weight loss diets, privately resolved to continue until they reach a target weight, and stop early. What would happen to them, in the counterfactual world where the diet was enforced perfectly from outside, and willpower wasn't an issue? Whether they would lose weight, seems like very much the wrong question to ask.

(Crossposted on Facebook)