Some people struggle very unpleasantly to get enough to eat.
Some of these people are fat.
Sometimes, being mostly unable to eat makes people lose tons of weight quickly.
This is not a good thing. It’s awful.
And it can make things worse for people. Talking that way can make it harder for fat people to understand that something is actually wrong when they don’t eat.
And even if they do know, it can send the message that you’re not a safe person to discuss this with, or that it’s not safe to eat substantial food in front of you.