Could it be "potassium" you are graving?
Thank you for mentioning potassium. That might be the thing about potatoes that messes me up. Yesterday I ate a banana and had insomnia and woke up with a miserable headache. I am taking some salt right now, maybe that will help.
I know it is widely know about needing lots of salt when one has POTS or orthostatic hypotension, but I never thought about the potassium angle.
If it helps, you have helped me solve a problem I have had for a long time. Thanks for sharing.