Seriously, when did this saying start? "You're not fat... I'M Fat!" This is the culture I grew up in. Anyone else? Is this a generational thing? A female thing? Telling anyone that you want to lose weight, be more active, eat healthier, results in this response or similar. I guess I can understand. A "yes. you could lose a few" response would be rude, but the "I'm Fat" tag at the end? What's that all about? You admit your flaw, therefore I have to deny it and admit my own? Why can't we support each other?
This mentality has lead me to keep my weight loss attempts a secret. I don't want to start the whole back and forth so I keep my efforts to myself which can work against me when I try to be healthy and need support from friends and family to help me make healthy decisions.
So, the next time someone apporoaches you and hints that they are trying to lose weight, notice how you reply. Maybe instead of focusing on weight and body image, change direction, and start talking in terms of health and better choices. Instead of "you're not fat, I'm fat" try "I'm trying to make healthier decisions. Do you want to work together?"