...you can't stop eating.
This is the single thing that has made it so hard for anyone I've known to lose weight.
In some cases, it's like telling an alcoholic to quit - but by the way they have to drink half a can of low alcohol beer three times a day for the rest of their life. No more mind you, but no less.
With other addictive substances, once the physical addiction's gone, you're left just dealing with the mental addiction. With food, you're still getting enough of those endorphins and increased blood sugars to remind you of what you Could be eating, every day for the rest of your life, let alone the psychological reasons people have for overeating.
We wouldn't expect alcoholics to have that self control so why do we expect those who have a serious eating disorder to suddenly man up and be able to handle it, just because we ourselves have done it, or because we never had a problem ignoring the rest of the cake in the first place, and then we ridicule them when they find it extremely hard?
I never understood the theory that making fun of someone would embarass them into eating less. People often overeat to give themselves comfort, embarassing them is only contributing to their problem. You might as well buy the cheesecake for them.
I have no problem with people who don't think "fat acceptance" is ok, given it's a medical problem, and people should be free to have their own opinions, particularly where they feel their life is being substantively impacted.
I do have a problem with people who translate that to mean it's ok drop the veneer of the polite society and call it hunting season on overweight people. I'm not referring to anyone in particular on this thread, but to the world at large (and it can be a cruel world).
I feel the same way about smoking too - I prefer to be seated away from it so that it doesn't affect me, and have an opinion about it, but I'm not going to be rude or mock smokers because (I hope) we still live in a civilised society, and they are just as much a member of that society as we are.