RDA in fasted state

Whilst the body is in a fasted state it runs more efficiently and that suggests to me that, in a fasted state, our bodies dietary necessities would reduce. For example the fasted state RDA of vitamin B12 would then be less than 2.4ug.

I regularly fast, sometimes for a couple of days but in between times my normal daily diet is a vegetarian 23/1. I’d love to hear people’s thoughts on this subject. Please post any thought you have.