How do I get my friends to accept me?

I have recently lost a lot of weight and my friends have been a little harsh. One group is convinced that I lost it because of cocaine though I have toldd them over and over that I would never do that. The other group of friends makes jokes like "are you going to eat? oh maybe a carrot stick, or a fat free diet yogurt" or theyll say, you used to be so fat, start eating, or go eat a burger or sth. I dont know what to do because it bothers me and I really do not like the jokes and they dont know (because I go away for school) that I worked really hard to lose all this weight. I eat better and I go to the gym almost everyday. I dont know what to do because I dont want it to be awkward, but it hurts that they make jokes all the time or dont believe me when I say that I just worked out and ate better.