Dr. Gundry has done an interview with a martial arts guy who was diagnosed with cancer, and fasted for 20 days only water, and 20 days a little meat and nothing else, and one or two sessions of chemotherapy or radiotherapy later he was clear of cancer. There are many people who talk about same experiences, from the patient side.

If some doctors are seriously researching fasting and cancer treatment, that's going to produce some measurements instead of relying on anecdotes.

I cannot find Gundry's interview, it's 5 years old something like that.

Fasting in general has been known for quite a while but (and I’m far from an expert) it only helps with certain cancers. Hell, I had a friend die this year from stomach cancer and he literally couldn’t eat or drink. He only went to the hospital when he was already skin and bones, got a few chemo treatments, and then it was too late.