So sorry to hear that. I'm not sure how old your grandma is, she probably doesn't mean to be hurtful. It reminds me of when I was a fat little kid and my overweight dad would take me to see his mom. She would practically force feed us all kinds of bad food and then called us her "little butterballs." It was hurtful.
I was just banded Wednesday. I've told my family, who are all very supportive. But I haven't told my husband's family because I don't want to hear their opinion and they all have big opinions.
Just keep doing what you're doing. It's nice to have outside approval but the best approval comes from within. Knowing you're doing a good job, knowing you're doing the right thing for yourself, and feeling good about yourself.