My personal opinion about a 'fat acceptance movement' is that it's all BS.
You partly judge people on their appearance for what you find attractive in looking for a partner or whatever.
You do not judge whether someone is a good person based on their appearance, but just in their actions, making fun of people for being fat in a friendly matter is ok, but bullying is wrong, obviously.
Though appearance can tell you a lot about the person, even the expression in someone's face can tell you what kind of person that someone is.

But back to fat people, when you're obese you're not living a healthy lifestyle, perhaps, in most cases, even an immoral lifestyle (though most people these days unfortunately view animals as commodities, rather then sentient beings).
Basically every major western disease can be reversed and prevented by consuming a whole-food plant-based diet, low in fat and high in carbohydrates. You can eat as much as you want, eat until full, every aspect of your health will improve.
I recommend checking out 'forks over knives' and in general the work of people like dr. Neal Barnard, John Mcdougall, Caldwell Esselstyn, Colin campbell etc.

If you are fat i would never recommend you to accept that, i would never recommend you to starve yourself, i would recommend you to change your lifestyle and consume a diet that you're physiology tells you to eat, no restriction, just eat what is actual food and that is plants, as found in nature, no oil, no dead animals, whose bodies you are able to recycle in a survival situation (though not without negative consequences).
And don't fall for all these BS things like blood type diet or whatever, you don't see cows with different blood types eat different things.. they all eat grass, a species specific diet.