This article, about a BBC show that looks at whether fasting is a good way to extend life in humans, talks in particular about Alternative Day fasting. You can also do it for just two days a week:
I decided I couldn't manage ADF, it was just too impractical. Instead I did an easier version, the so-called 5:2 diet. As the name implies you eat normally 5 days a week, then two days a week you eat 500 calories if you are a woman, or 600 calories, if you are a man.
There are no firm rules because so far there have been few proper human trials. I found that I could get through my fast days best if I had a light breakfast (scrambled eggs, thin slice of ham, lots of black tea, adding up to about 300 calories), lots of water and herbal tea during the day, then a light dinner (grilled fish with lots of vegetables) at night.
On my feed days I ate what I normally do and felt no need to gorge.I stuck to this diet for 5 weeks, during which time I lost nearly a stone and my blood markers, like IGF-1, glucose and cholesterol, improved. If I can sustain that, it will greatly reduce my risk of contracting age-related diseases like cancer and diabetes.
Current medical opinion is that the benefits of fasting are unproven and until there are more human studies it's better to eat at least 2000 calories a day. If you really want to fast then you should do it in a proper clinic or under medical supervision, because there are many people, such as pregnant women or diabetics on medication, for whom it could be dangerous.
I was closely monitored throughout and found the 5:2 surprisingly easy. I will almost certainly continue doing it, albeit less often. Fasting, like eating, is best done in moderation.It does sound relatively do-able, I guess.
Whether it's good for you still seems up in the air, though.