Are nutritionists or naturopaths classified as complementary and alternative medicine?

Yes ND's,some nutr's. Naturopaths by definition practice what is sometimes called complementary or alternative medicine, as they tend to recommend natural therapies such as nutritional supplements and herbs. Some nutritionists have an approach consistent with complementary and alternative medicine, while others are more mainstream in their approach, so it depends on their training and philosophy.
Naturopaths. Complementary and alternative medicine are favorable terms for practitioners who debunk allopathic medicine and apply general theories of treatment not supported by clinical evidence. Nutritionists generally have extensive higher academic training in foods, vitamins, nutrition, etc. And are a useful part of the health care team.
Proven vs unproven. By definition, "alternative" is different than modern western medicine. Generally any drug, herb, treatment, or procedure that stands up to rigorous scientific scrutiny is included in modern medicine. The problem is that many alternative practices, herbs etc do not stand up to scientific scrutiny and cannot be shown to work. They therefore remain "alternative". Be careful and watch your wallet.