Being hared by friends for eating healthy?

There is one friend in particular that is on me constantly about everything I put in my mouth. She's overweight, and that's none of my business. I believe that what you eat is your choice and no one else should tell you what you should eat. She wasn't always overweight, when she was in high school she was anorexic. She says she doesn't eat a lot, but I see her eat a lot of fast food, and sugar and stuff. She tells people she doesn't eat sugar or soda, but I do see her eating those things. Again, I don't even care. If she wants to eat cake, an tell people she doesn't eat sugar, it's none of my business, and doesn't effect me. She does make little efforts to eat healthy, but that's by buying the occasional less fat hot pockets, or sugar free puddings. I think that it's more to make herself feel like she is making an effort. She wants to feel healthy, without actually being healthy. Again, it's none of my business, and I don't care. I'm just telling you so it will explain what she's doing to me. I try to eat healthy. I eat sprouted grain bread, brown rice puffs cereal with honey. I drink soy milk instead of milk. I don't eat meat. I eat plain Greek yogurt, and gfruits and salad. And I feel like she is in a competition with me in her head. She is very competitive. I feel like when she sees me eating healthy, it reminds her that she doesn't actually eat healthy, and disillusions her, making her feel bad about her weight. I feel like she also is in competition with me to "eat healthier" she constantly, constantly tells me the 100% juice I'm drinking is bad for me because it has sugar in it, while she drinks sugar free soda. She told me the soymilk I was buying was unhealthy and her milk was healthier. I said my soymilk doesn't have cholesterol, saturated fat, antibiotics in the cows feed, or growth hormones, it does have added fiber and milk gives me terrible stomach cramps. But she still said my soymilk was worse than milk. She's also said my plain greek yogurt was the most unhealthy yogurt in the store while she ate hot pockets and cookies. She also pressures me or makes fun of me if I'm not hungry or I don't share the cookies they are eating. I think it's because she feels better about eating junk food if I join in. Also, when I do grant myself a piece of pizza, or birthday cake, she announces triumphantly that I eat unhealthy, I always reply that my diet is good enough to allow a little living in. I'm really tired of this competition. I'm really tired of eating a cookie I don't want, just so she doesn't har me. What should I do?