Here's what we're going to do.
We are going to approach the subject of my health as if it doesn't solely depend on the amount of fat tissue I'm carrying with me.
We are going to treat me as a human being, not an ambulatory pile of lard.
We are going to look at possible decisions for my life and my health based on whether they're actually good for me, and possible for me, and not whether they'll lead to a reduction in the size of my body.
We are going to acknowledge that I feed my body as well as I can with the resources I have available to me, and that I do get exercise even if I don't particularly care to go to a gym. And we are going to acknowledge that these things are good for me even though they have not led to a noticeable reduction in my body's size and weight.
And here's what we're not going to do.
We are not going to talk about my weight as if it's the only possible reason why anything would go wrong with my body.
We are not going to deliberately try to reduce my weight, because I've done a lot of damage to myself—both physical and mental—while trying to shrink myself, and I've come to the conclusion that it's safer and healthier not to do anything for the express purpose of getting smaller.
We are not going to approach the subject like my clothing size is a disease.
We are not going to use death threats (i.e. "lose weight or you'll die of something terrible") to "inspire" me to become thin.
We are not going to talk about me as if I want to be a size and shape that are subject to huge amounts of social stigma (I don't), or as if I got this way by constant overeating and copious amounts of junk food (I didn't).
We are not going to put me on a diet that's so restrictive that even a moderately-active five-year-old would feel starved by the amount of food it would allow me. I've done that already—on a doctor's orders, no less—and it didn't do anything good for me.
We are not going to treat me as if the only way I deserve to be treated with respect (or even basic courtesy) is for me to become thin.
And if you can't accept these terms, then there is no room for you in my life. You are not good for me, and I cannot trust you with my health.
(Inspired by this post by silentbeep. If you click through, be aware that she's posted a trigger warning for weight gain/weight loss talk.)