I don't want to spoil your fun, but I think there are already a thread like you can join. I know that you want a BODY-challange thread, but the Diet & Weightloss thread might be just what you are looking for we moan about everything there - AF, gym, food, bad food, good food, weight ect. Why not come and have a look and see if you will get the support you need there
GOOD LUCK - it sounds like a good plan.