The Science of Fasting

A guy I know at yoga went on a 7 day fast at the end of 2017. He said he came out of it feeling more alert and everything seemed more vivid. He also looked skinnier (he was a normal size to begin with) than before he started.

I want to try a fast but I work out once, sometimes twice per day. I'd have to stop working out in order to do it. Perhaps I should try one or two days and work my way up.