How does fasting work?

[orlandobbb]

Am looking to loose a stone and a half and wondered if this could help me but I don't understand how it works and there also seems to be a 5:2, 16:8 and other versions- are these different diets?

5:2 is where you eat 'normally' on 5 days and cut calories to 500 on 2 days
16:8 is where you only eat during an 8 hour window (so therefore fast for 16 hours each day) every day. So you might eat at 12 and again at 7pm.

There are support threads for both on here.

Both work by allowing your body to reset its insulin function, and by the nature of them you also reduce your overall calorie intake. I think in practice you need to modify your intake on the 'eat normally' days, as if you are prone to overeating you might not achieve the deficit you need to lose weight.

I personally haven't had any success with intermittent fasting diets, and found the blood sugar diet (written by the same guy as the original 5:2 diet) to be most effective.