100% agree with everything you said. Feeling cold is one of the major symptoms I get when fasting for a few days or undereating on purpose. I can only do it for so long before I get chilly, can't concentrate, get irritated, my immune system seems to shut down and I get a cold..

I'm basically looking for that "switch" you describe. Whatever it is that makes the body turn up or down the furnace while leaving you satiated.