I have been LC-VLC for over 4 years now - get cramps on occasion, when I do I just up my potassium & magnesium intake for a day or two and they go away. Only pattern I have noticed is if I have been very active in hot weather I may get a cramp, so dehydration may be a factor.

I had these as well; used to happen especially when lying down or foot is in a weird position. It would trigger a cramp and my toes would cross over. Not painful but very weird and it make me get put some pressure on my foot to relieve it.

I did a 7 day fast (and ofc following paleo diet) and I don't get it anymore.

In some people, cramps like these go away with the addition of a little extra salt to the diet.

I've had these happen on occasion, once when I added a commercial heavy cream packet to coffee at work (the kind that's in a small sealed plastic container and lasts for months without refrigeration and has some funky additives.) Perhaps it's just a coincidence. This was in the colder months, so not related to sweating. Or perhaps something about the cheap office coffee - but it didn't repeat with just black coffee.

It's a very weird feeling, as one of my toes decided to move to the left, and that being not an often used muscle (I don't think I can consciously move a specific toe to the left or to the right, just up/down). It fatigued very quickly and became painful. Pulling it back to center with my hand, I noticed resistance - it really wanted to go left. Sort of like a nerve-short circuit.

Taking a magnesium capsule got rid of the cramp within 20-30 minutes, so as other answers here report, it has to do with mineral balance. I'm not on a low sodium diet by any stretch, so perhaps low magnesium (or too much of another mineral that magnesium balanced?) has the same effect.

I've had a repeat of this on other occasions, and the magnesium trick fixed it each time. The 1st time, it lasted a very long time because I had no idea what to do, so I doubt it's a placebo.

try soaking feet in epsom salt (it has magnesium) or try rubbing magnesium oil into skin. works also for leg cramps.

I now think I know why:

How many carbs do you eat on the days you get cramps in your feet?

The upshot is I get these cramps on days with high carbs- especially noticeable on days when I eat dates. Obviously, more experiments are needed, and some kind of theory about why would be helpful. I feel compelled to eat more carbs since I am working out, but the cramps make me wonder if it is a bad idea.