but long fasts and keto aren’t sustainable for me (not being able to regularly eat carbs would suck too much of the joy out of my life).

That being said, I typically do a daily 14:10 intermittent fast (limit my daily eating window to 10 hours or less) and workout toward the end of my 14 hour fasting window.

Saturday night into Sunday, I usually do a 16:8, but 16 hours is about as long as I ever fast (I start getting headaches and just feel generally weak and irritable if I try to fast much longer than that).

I also keep myself on a pretty regimented eating schedule most of the time (plan all of my meals and snacks out in advance), which is significantly lower in carbs (and higher in protein) than the standard American diet but nowhere near keto.