How to handle my mother and her issues with me?

My mother has a tendency to just look at me an just say that I need to lose weight and it really aggrivates me and upsets me so much...sometimes i just sit there and cry...everytime i get my checkup..the doctor says that I have a healthy weight and that I am fine and healthy. So im not overwieght. Buh then everytime she says it ...ugh i get pissed and feel like starving myself...someone help me please