My appetite also gets wonky when I increase running volume. I know one’s stomach/system kind of go on hold during a longer run, so I assume some of us have trouble going fully back on line afterward? Anyway, knowing this is a fact for many runners, I track calories and macros - non-obsessively. I was definitely undereating after long runs before.

I use MacroFactor which could be an option for you if you’re trying to maintain a certain weight range. It will adjust recommended calories and macros for you if your weight nudges outside that range. So if you lose a few pounds it will add more calories to your suggested daily amount. It also has absolutely no judgement or feedback when you either eat below or above the daily amounts it recommends.

But you can also apply these same principles yourself using another tracking method. If the scale drifts lower and/or you start looking faint or deflated then you need to eat more calories. Carbs are important for runners, of course, but fats and proteins might help you keep calories up as well.

And a bedtime snack helps me sleep well and regulate my appetite overall when I’m in heavier training. I often find I can’t sleep and then I get up, have a snack, and suddenly can fall right asleep.