They say the average is a stone a month, but the heavier you are, the quicker it goes. For example, moving from 22 stone to 16 stone will take less time than going from 14 stone to 8 stone. I think giving yourself 6 months is probably a realistic guess. I hope that helps. I've lost three and a half stone in two months but, as you can see from my stats, I started at a very heavy weight, and of course everyone's body is different and reacts to the programme slightly differently. Good luck though, if you choose Cambridge as your route - I recommend it!