This is probably an idiotic question, but I've been doing anapana, Goenka-style vipassana, metta, mantra stuff up to a few hours a day lately, and now I have this constant buzz, mainly in my hands and feet. Is this a thing in meditators, or should I be seriously concerned that I may have developed insulin resistence? I've also been eating once a day in the past two weeks, but I'm starting to suspect that I've been doing it very badly, since I crammed a ton of carbs and fats at night in a desperate attempt to get enough calories to survive - I don't have fat to spare, I fast because I have bad reactions to most most foods and I don't want to be ill all the time. Can you get insulin resistance from fasting and binging? I've also been having mad gingivitis, which apparently is also indicative of insulin resistence. Man, I suck.

The buzzing is common phenomena caused by meditation practice. You are noticing the impermanence of bodily sensations, it's good stuff to continue to be gently aware of. For most people, hands and feet are among the more sensitive areas in the body so this is often where buzzy, vibrating sensations will first be noticed. If you want less buzzing, you can back off from practice for a while. 

For your medical concerns I would encourage you to seek a doctor's advice. 

I never have much luck with fasting. It cranks things up faster than I can cope. If you can note it, you are one step ahead of the game.

Makes sense. I just hoped someone here is knowledgeable about fasting in relation to meditation, and whether intensive practice can have such strange effects as gingivitis or insulin insensitivity. Also, I can do all the tests, but maybe the same results could mean something different for a meditator. I guess I wasn't clear in my original post.

I'm not sure what you mean. If I can note what?

When I started noting in earnest, I was so intense that I can't remember what I was bothered about. I made the three characteristics my guide.

Physical symptoms are usually present when people start noting practice.