It would be one thing if we were talking about rubbing crystals all over your body. I would not consider a modified diet "alternative" medicine. There is legitimate science around diets and how it affects cancer growth (see TED video):
On the other hand, as naturopathic doctors themselves explain, "tradition-sensitive naturopathic practitioners ... which have tradition-based paradigms articulating vitalistic and holistic principles, may have significant problems in relating to the idea of EBM as developed in biomedical contexts." http://www.liebertonline.com/doi/abs/10.1089/acm.2006.12.323