Hi allie, its very similar to lighterlife. You buy satchets of soup, shakes, bars etc. and you eliminate all other food (if you do sole source) but there are other less strict varients of the diet. The good thing about it is you dont have to think about food, calories, fat content etc. as its all done for you! look up the cambridge diet web site. Good luck
If you visit the post there's a link to the Cambridge FAQ page where you can read more about the diet.
If you have any specific questions, try running a search (top right of every page) and read through the stickies. Any further questions once you've done that, if you post on here or the main Cambridge page there's usually someone around who will try to help you!