answer:Different fasts have different effects. Depends on the time and what ingredients are removed from your diet I believe. I am not a scientist though. I do know that when I quit smoking, I went on a three day water with lemon fast. I only drank that and ate nothing. After three days, I only ingested green vegetables with brown rice for 28 days. Part of a diet detox program I read about. It was possibly the hardest thing I have ever done but I have been smoke-free for over a year now. I gave up caffeine and nicotine at the same time. The cure was hard to do and I think that had a lot to do with it. I don’t want to go through that again but every few months, I do the water with lemon for 3 days because it makes me feel better. Is it scientific? Nope. I just feel better and I believe it does something of added health benefit.