I just logged on to prevent myself from going into the lunchroom and eating " bad" things and saw this string. So many of the reasons others have given I have to agree with.
I was invisble . Looking good attracted too much attention and I was extremely shy growing up and still today, feel inept so being overweight was less threatening .
It was easier to do nothing and be unhappy about the weight than to actually do something and have to keep doing it everyday to acheive and retain results.
Fear of failure. If I tried, then everyone would know what a loser I was ( of course I assumed I would fail)
I didn't want anyone to know I cared what I looked like. I was supposed to be better that that. I didn't need make-up and did n't do my hair, etc. I wasn't supposed to care about such "superficial " things.
and so on and so on... a couple of decades of mindset is hard to get rid of... but I'm getting there.