Fat acceptance is something different to each person. Some accept that they aren't willing to change, some accept the fact that they'll always be big while some go to extremes to lose the weight. My cousin and I have been big since we were little. While we were kids he was heftier than me but we had pretty similar builds. Our freshman year in high school, we started playing football and lifting weights, while we were both getting stronger I started to grow into my fat more than him. By the end of our sophomore year, I was chubby at about 225 and he was pushing obesity at about265-270. Over the next summer we diverged paths and didn't level off for a while. Towards the end of our sophomore year my cousin decided he was fed up with being fat after having a girl tell him he was "cute for a chubby guy." I on the other hand maintained about the same amount of body fat, but my frame kept growing. By the time we came back for our junior year we had both changed quite a bit. He had lost about 80 pounds (putting him at about 195) over the summer and was barely recognizable to alot of people. I still had a bit of extra weight on me that never went away despite the fact that over the next year or two I'd be in the best shape of my life. I could run 5-10 miles no problem when I was 265-270, most wouldn't say I was fat, but I wasn't cut or buff or anything. I totally disagree with:"Diets don’t work. No, really, not even if you don’t call them diets." However I do agree with:"Weight itself is not a health problem..."
DaveB was right when he said that this is much more of an issue of cosmetics that we'd like to admit. When my cousin lost his weight, he did it in a fairly unhealthy way. Running several miles a day while eating maybe a sandwich or bowl of soup all day. He was fucking sick of being fat, but more than anything he was sick of being seen as fat. I on the other hand didn't worry about whether or not I had a six pack as long as I had the stamina and strength that I wanted. You can debate as to who was healthier, but I'm not sure there's much debate as to whose motives were healthier. I think I made peace with being a big guy and embraced it, he rejected it feeling it would be the best way to get girls. In the end we were/are both huge pimps.
If someone does their best to be healthy, I say they should accept their fat.
Changing one's body for superficial reasons is all good, but the frame of mind that leads to it can possibly lead someone to overdo it, whether that be binge eating or starving.
ETA:Fuck the BMI.