This is how it develops. In high school there were so few fat kids, and the ones that were fat were very obvious lazy POS. As I became an  adult, and more and more in an office setting, i realize people are just making excuses. Yes commuting to work sucks, and sitting at a desk for most of the day sucks, but the majority don't watch their diet and are constantly making excuses, justifying why they can/can't eat that birthday cake, or why their new diet is going to work. My coworkers for over 5 years continue to think I'm about 10 yrs younger because I didn't become a fat POS (I'm 31). They constantly joke about initiation being gaining 10 lbs bc there's so much junk at the office. It annoys me to no end because they like to make comments about how I CAN and do eat that birthday cake because I'm naturally thin. It annoyed me so much I've started contributing to the conversation by saying I want to GAIN weight, even though I'm already somewhat "uncomfortable" (I'm 5'3 female, 116 lbs, athletic appearance aka you can somewhat tell I work for my body). I love the looks on their faces when I "complain" about how hard it is to actually put on the right muscle weight. HA.