When I was younger I had a hell of a time keeping weight on me. I was still very curvy, but I was always bordering on being underweight (which was odd cause I had DDs and a booty). After having a child I am overweight and have developed PCOS and struggle to try and lose weight. The shift in looking at how I eat, and how I take care of myself was huge.
The worst part was realizing how truly different people treated me. I was always self-conscious when I was thin, because guys only seemed to be interested in me for my looks. Now that I'm a big girl, most aren't interested in me at all. My self-esteem has dropped more from how people treat me than the fact that I'm not happy about the weight. I think the attitude of people (guys especially seem to be bad about this) towards overweight people is pretty sad. They don't understand that it isn't as easy to lose weight as it would seem. Dieting really is not realistic, and one can only exercise so much a day. My grudge on dieting actually comes from research (I learned this recently after subjecting myself to calorie restricted diet for about a year), restricting calories causes your body to make do with less and store anything over that. It takes over a year, and often at least 2 years for a person's body to adjust to a normal calorie intake after restrictive dieting - this means that people yo-yo in weight going on and off diets. There is no simple way to start eating normally after dieting without gaining weight back, so its a struggle to make it work.
Even knowing this, when I talk to doctors about my concerns about my weight - all they ever say is eat less. Even when I was on a 1450 calorie diet (doctor suggested even), it was eat less. I hate that it is assumed that anyone overweight eats food like McDonalds everyday. I completely agree that it is just sad how focused society has become on size and looks - and commercials definitely reflect that. Even on the internet half the ads you see have to do with weight loss.