I had a go earlier in the year and kept it up for a couple of months. I did feel the benefits and think it is so successful because you can eat the food you want. I am not doing it now but it has helped as I have cut down on portion sizes and don't eat as much 'junk'.
I do still enjoy 'pigging out', but I plan ahead ....... salad for tea then an hour or so later wine and a big bag of doritos .... yum
This is the diet that says 2 days a week (it needn't be the same two days each week) on 600 calories and don't worry on the other 5 days (i.e. eat normally not blow-outs). I have been doing it since February and it seems great, it is the first one I've managed to get my husband to adopt (His Body Mass Index was too high before so we were worried for health reasons). On the day we have 3 '200cal' meals which is for us a pretty much normal breakfast, soup for lunch and a small portion of meat with masses of green veg in the evening. I would love to know how anyone else is getting on and if anyone else has tried it? Lots of my friends seem to be starting it. I have to say it is working for us, but I don't see how we'll ever be able to get off it!!!!