I started fasting about 3.5 years ago. Originally, I could get cold at some point during a 4.5-5.5 day fast. Then I started getting cold during my 3.5 day fasts. Lately, if I attempt to fast 22 hours (which is basically one meal a day, OMAD), my hands get so cold I can’t touch myself. And if I try to make it 36 hours, I have to have a bunch of covers on me at night, in the summer.
As soon as I eat, I get warm again. That is, my hands return to their normal temperature.
So, I’m giving up on fasting until this effect goes away. I will eat when I get hungry.