I think intermittent fasting has a pretty good rep (reputation). It's just fasting on and then off. Like this, for example: stop eating at 5 p.m. and start eating again at 8 a.m. the next day. Then eat normally until you start it again at 5 p.m. There's a lot of information on the internet about how people do different kinds of intermittent fasts, but that is just one way. I think the easiest part is sleeping through the fast!
For longer fasts, ask your doctor. He or she would have a better opinion than mine!