My model of weight gain is that the most common way for bodies to work is to be like a ratchet: they get used to holding onto more fat, and then fiercely resist giving it up. Which means if I like my current size I should be careful about unintentionally getting larger. I don't have a scale at home [1] and had been only weighing myself occasionally, but ~18 months ago I realized I'd gotten about 10% heavier. This had happened over less than a year, and is something I'd been thinking might happen at some point: my father also had a metablism shift at around this age.

I decided to start trying to pay attention to this, and over the next ~6 months slowly got back to the size I wanted to be. Here are some things that worked for me:

• I started taking smaller portions, and then getting more if I felt hungry after. Before I would sometimes take more than I would turn out to want to eat, and then feel like I should finish my plate.

• Relatedly, I switched to a smaller sized bowl for breakfast on weekdays, and discovered that I still felt full after eating.

• I stopped eating as much dessert. I had been eating cafeteria desserts every day, and I switched to eating them only on days when I was excited about what was available. I also had been putting half and half on many things, and stopped doing that.

• I stopped finishing Lily's bedtime weight gain shakes. I'd been making very high calorie drinks for Lily (3y), since she was having a lot of trouble gaining weight. They were very tasty, and I would often make extra so there would be more for me to finish when she was done drinking. Once I shifted my sense of eating from "eat whatever" to "be somewhat cautious and prioritize" it was clear these weren't a good choice.

• I brush my teeth with something minty and have built up a strong sense that I shouldn't eat while my mouth still has a minty clean feeling. So if I brush my teeth after each meal it reduces the time when I might snack.

• I've noticed I don't really get hungry until I've gotten out of bed. I also sometimes focus better if I start working on something as soon as I wake up and don't do anything else until I'm done with it. So occasionally I'll start working something on my laptop in bed in the morning and not eat until dinner.

• Wearing a bit less of a coat than is comfortable in cold weather so I'll be a little cold and want to run.

Overall, these have been a bunch of small things, and as in many cases it's hard to tell how much of an effect each one had. My guess is that the main effect is from reducing how much I eat when I'm not hungry, or eating past when I stop being hungry.

[1] Actually, between writing this and publishing this we did get a scale: when flying it's really helpful to know if you've kept your bags under weight limits!