There is a certain decorum to maintain with a person. There are always lines you shouldn't cross. No matter how close or distant you are, you should always watch the lines. Just because she's a good friend of yours doesn't mean that you can call her 'mooti' all the time. She has issues with her weight, that doesn't mean its open ground for you go publicize and make fun of her. Just because she doesn't say anything, doesn't mean it doesn't hurt. Who are you to talk like that? Just because she doesn't say anything, doesn't mean you can make disparaging remarks about how her arms resemble meat loaf. Do you think you're being funny or extremely smart by saying so?