I have a hard time imagining that you would feel grateful if someone said to you "maybe you shouldn't wear that bathing suit." What do you expect people to tell you exactly? That you're fat and you need to lose weight?
I've always hated statements that allude to being overweight... "Are you SURE you want french fries?" or "maybe we shouldn't have dessert." My Mother always tried to say something about it but she would get this pitiful sad look on her face and whisper "please, please don't gain anymore weight" as if I was a heroin addict shooting up in front of her and breaking her heart.
What's important is that you're telling yourself now! It takes a long time to climb out from the depths of denial - ahhh blissful denial... the denial that allows us to eat and eat and eat without a single calorie passing through our minds

The only person that can snap you out of that is yourself. Any comments from anyone else will only make you feel awful but it won't do much to help you get out of denial.