I like his straightforward speaking. Not embellished. Simple and believable. I'm also impressed, as I usually am, by people who make drastic dietary changes later in life, by choice.
Since I saw this at T. Colin Campbell's site, I suspect the diet Mr. Hale was following was similar to what Drs. McDougall and Esselstyn promote - a fat-free, plant-based (vegan) diet. It excludes all meat, fish, eggs, and dairy - cheese, yogurt, butter, etc. There is no added fat or oil. There are no packaged, processed foods. It is essentially a diet of whole grains, beans, vegetables, and fruits.
Note that he said he ate a lot of cheese. In previous posts I noted that a 2001 Harvard review of the body of evidence at that time on dairy intake and prostate cancer found:
"[Consumption of dairy products] is one of the most consistent dietary predictors for prostate cancer in the published literature."