Family tries to make me feel fat?

My mother tells my grandmother that I eat so many potatoes and says she eats like 3 a day (I don’t) and goes through them so fast. I’ve commented about my weight before I’m 136 pounds 5”8 and she just says yeah, that’s what happens and agrees when I mention parts of my clothing look bad. . She says it’s because I eat carbs. My grandmother said I live to eat instead of eating to live. I don’t know why she does this.