I decided not to tell anyone other than close family for all the reasons stated in this thread, and i used most of the ideas people have used or suggested to create a cover story, and so far its worked pretty well, but people still ask how i've done it and i now have trouble continually lying to them ! - you see when you start out lying you have to continue lying and one lie leads to another and another and it gets harder and harder to maintain or remember what you've told people ! and now i want to tell certain people i really cant because i know when i do they will be hurt thinking i didn't trust them enough in the first place........ its vicious circle of deciete that goes around and around !
So my advice would be to you, which ever way you decide to go think about it closely, remember those friends that really matter wont mind what you do, those that dont matter will mind or have an opinion !
PS Neighbours (in this case is easy to blagg) tell them you've cut down and taken up exercise, they will be non the wiser, the weight wont fall of over night, so you can blagg it !
