I do 24 hours 1-3x a week but with a twist. Most people think "24 hours" and think "in the same day." I will eat breakfast and lunch one day and then nothing until dinner time the following evening. It still accomplishes the 24 hours (more like 27-29).

I also generally exercise at the start of the fast to burn off my glycogen stores so my body relies on stored fat for energy the next day.