Ive done and know several people who do lighterlife and the cambridge diet.
Lighter life is about 65 a week
Camberidge just under 40 depending who/where you go
They are both very hard very intense diets. Which give you very quick results IF you stick to them to the letter. There is no point in doing these if your a diet cheater, as youll actuall not loose any weight on them. I relys on you sticking to them to the letter.
Although i know people who have lost anywhere from 1 stone to 10 ina very short perios of time, i dont know one single person who has kept the weight off. Basically its an expense hard quick fit which like any it doesnt work in the long term
However ive dont it 3 times (the cambridge) but basically its impossible to keep the weight off. My friends is one of the 'examples' they show you as she lost 10 stone in 9 months. But what they dont tell you is a year and a half later shes 11 stone heavier again (if not more, but i darent ask!)
If you fancy giving it a try id say go for it, just dont expect the weight not to creep back