But going to a naturopathic doctor for a diet prescription is rubbing crystals all over your body. William Li (the speaker in that talk) is an MD bringing evidence-based medicine (i.e. science) to bear on the question.

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

There's a few big steps from a good theory with solid science to a good theory that's been proved via large scale studies to a possible cure to a cure that shows promise in small targeted studies to a cure that's been validated via large scale studies. The vast majority of possible cures get discarded at each of those steps.