EDIT: I didn't mean to say that changing to a healthy diet/lifestyle after being diagnosed will magically cure you (if that's why I'm being downvoted) but I believe it certainly can in some cases. If it's for lack of references, well, when it comes to cancer, you can find a study to support just about any view you want.
This is the most stupid and obnoxious thing I've ever seen on HN. Chemotherapy saves lives every day. You can believe that good diets are healthy and helpful for sick people without insulting people that sell nasty but powerful medicine that is proven to work.
http://www.ncbi.nlm.nih.gov/pubmed/?term=turmeric+cancer
http://www.ncbi.nlm.nih.gov/pubmed/?term=piperlongumine+canc...
http://www.ncbi.nlm.nih.gov/pubmed/?term=bromelain+cancer
http://www.ncbi.nlm.nih.gov/pubmed/?term=frankincense+cancer
https://www.google.com/search?q=ashton+kutcher+fruitarian+di...
It's the equivalent of saying you could cure cancer with diet.