I had this same problem. I used to always pit my shirts out. I went keto, regularly fasted, and lost 20 lbs. My overactive sweat gland calmed thr hell down and i no longer have this problem. Unexpected benefit I guess?
Hyperhidrosis can be a parasympathetic issue, occasionally induced by use of psych medication in the past/other otc meds. Can also be a lymphatic issue. Could also be weight and fitness related. In my experience, and opinion, dry fasting would prove beneficial only if it’s pathological.
Some people are just heavy sweaters by nature though. You can go to any boxing gym, all the top boys at peak fitness, ones sweating his bag off. Just the way it is
It sounds like this is not just ordinary expected sweat to you. Medicines can sometimes cause that effect like some anti-depressants.
Some illnesses too. I guess you are hoping to either knock out an illness or correct an imbalance caused by eating. It sounds reasonable dry fasting could help those 2.
I have seen some video that mentions sweating, it think it might be this -it’s not about fasting but about salt and some other key minerals that we apparently don’t get enough of. https://www.youtube.com/watch?v=kXZo0hSHDoY