I tried Cambridge - costs roughly �33 per week (each meal replacement shake or bar costs �1.55) and you will need 3 shakes or bars per day (4 if you are male or over 5' 8" in height) and you also have to drink at least 2-4 ltrs water per day. I personally found it very hard, after a few days you do stop feeling hungry, but i never really got over the weak and enfeebled kinda feeling i got from doing it - sort of shaky & lightheaded and all my muscles ached and i had no energy. plus it gives you really bad breath, the kind you can tell is coming from inside your stomach, brushing your teeth does nothing to eliminate it & chewing gum isn't allowed. every 5 weeks, if you have not reached your target you have an "add-a-meal" week where you have your shakes and a small meal consisting of a tiny portion of white protein (chicken, fish, tofu, quorn or cottage cheese) and 2 tbsp of green leafy veg. i had to give up Cambridge after 3 weeks, i collapsed at work and my blood pressure had plummeted. my Dr literally said "quit the diet or die" so i came off it and am doing slimming world now and am much happier. the weight losses on Cambridge are good - i lost 9lbs in my first week and roughly 4lbs a week after that. people say they tend to lose around a stone a month, but going without food is very very hard - the smell of other people's food drives you insane and every advert on telly seems to be for food. i'd say go for it if you think you're psychologically in the right place, but be prepared to have to quit, like i did, if it makes you physically ill to do it. good luck!!