What should I do about my couch saying I have to lose weight?

I go to a very well known high school where excellent athletics is a tradition. I am on the track team and I am a very good sprinter. I am 5'7 and weigh 136 pounds. I do not believe a couch is aloud to tell a high school 16 year-old girl she has to lose 6 pounds. My male couch told me i had to do that. I've noticed in past years that he has made some rather rude remarks about my weight. I never ever thought i had a problem. All the girls are just very naturally slim. I am slim, it's just I was "blessed" with a completely genetically big . I have a flat stomach and everything is slim, except for my . People like me for it though. They think its nice to have a chick with curves in that area, but my couch doesn't think so. Anyways, I feel like quiting now because I feel like I'll get hared by him and end up reporting him. I don't want to because hes retiring this year and he is overall an awesome coach. I just don't want to cause conflict and tell him off either. It's not just him but I feel I really need the break from track and do it my senior year(next year). Does anyone have any advice on what I should do? I don't want to lose weight because I like my body the way it is.