I had terrible pain in my knees and thought it was from ballet classes. Ice packs helped a little, but not enough. Even after I quit the ballet lessons, my knees still hurt whenever I did jumping lunges or any type of high-impact exercises. After I removed the majority of items that contained sugar from the cupboards and the refrigerator, I noticed that my knees stopped hurting. Apparently this is more common than I thought. Sugar causes joint pain! Now that’s another good reason to stop eating sugar. Sweet!