Please, please be considerate of your fat friends' needs and limitations.
Fat bodies are heavy to carry around. I move about the world slower than my thin peers, and I've often had to choose between pushing myself to keep a pace that takes absolutely all my energy, or being left behind, when walking in a group. I don't always feel safe to ask that everyone walk slower, because there's a prevalent idea in society that fat people need to exert themselves as much as possible at all times in the service of weight loss, and that we never "really" need rest, therefore it's a good thing whenever we're exhausted. Fat people and thin people alike are taught that fatness is a flaw, one that fat people ourselves are to blame for, so we're not entitled to any accommodation or consideration.
A friend of mine who is fat recently told me about a dinner party she went to where the chairs were far too small for her and she was sitting very uncomfortably. After the meal she politely suggested moving the party to the couch, but the others didn't want to. She spent another couple of hours in unnecessary pain, and didn't dare tell them about it.
I love my thin friends, but some of them just don't realize that I weigh probably twice as much as them, and yet I balance it all on the same size feet and carry it on about the same size bones. I'm like if they had a whole other them to carry around at all times. Why would that not have an impact on how I function?
Please - take us into consideration when we're part of activities. Ask us which activities work and which don't. Adjust the pace so no one has to be dry heaving and sweating barrels on what's supposed to be a casual walk. Make sure venues have seating that fits us. Make it safe for us to speak up if we need something. When we do, don't treat us like we're the problem.
Finally: yes, we have heard of losing weight. Even those of us who might (and many never will, whether you like it or not), won't do it on a moment's notice. If your response to "fat people deserve accommodations" is "what if they weren't fat though", you're playing a fantasy game. It's pointless. We are fat and we are here and we do partake in society. Work with that.