Beauty is a very subjective matter, but some people don't have that common sense of not commenting other people's weakest point straight to the face.
I do believe that we can give comments... but do bear in mind that our words might hurt someone's feeling although we might say "I'm only saying the truth".
That's why, Malay culture is full with courteous acts. We have to think carefully before we say something silly.
Recent case :
I tried my best to look good for my husband and students. I started to wear make-up just because he asked me to wear it for him. Wearing nice clothes just for him makes me happy. So, there's nothing wrong of changing my old self just to make him happy.
But...there is a co-worker here who will never think twice before uttering unpleasant words.
He said to me one day, "I thought you are someone else looking from behind - younger. But...huh...looking at your face now, you are not really attractive."
Because I have learned his characteristics from my friends here... I don't really feel intimidated for what he had said to me, instead I answered him proudly, "My husband thinks I'm beautiful enough for him. I wore this attire with his permission. I wear make-up just to please him... I'll get the pahala if he is pleased with me."
He couldn't say anything to intimidate me anymore after that incident.
My advice is... if people complain about your look, weight, body or anything that might hurt your feelings, it is best for you to take a deep breath and then tell them that you are proud of who you are. It will not look good on you if you answer them angrily. Smile... then they will never say unpleasant things about you ever again.
Just be calm and let them know : I feel proud of myself and who are you to judge me????!!!!