OP, I feel your pain, but I weigh so much more. In spinning today I worked out I weigh nearly 18 stone. (Converting pounds to stone on a whim during the cool down) 

I don't eat brilliantly like nothing but steamed fish and broccoli but I rarely have a chocolate bar or crisps or biscuits, and cool almost everything f from scratch, I eat from small bowls and try not to have seconds. I actually don't think I look like I weigh this much - I really hope not.
But here is the real kicker, I pretty much go to the gym every day - I do yoga, spinning, Zumba, TRX and play badminton and squash. And I don't do these things half-heartedly, I work up a mega sweat and get really red in the face. On top of this I walk my dog twice a day, usually doing between 4 and 6 miles a day at a briskish pace. And then all the stuff around the house chasing a toddler.
I'm so embarrassed, I must be deluded, I really, really don't know why I'm so heavy. But I don't think exercise is my answer, it makes me feel better and I hope it makes me look better but to drop the Wright I'm going to have to really eat loads less. Sorry to derail but any advice from anyone would be so appreciated.