I found him! It's
Dr. Frank B. Minrith. Sure there are several out there who teach blood type diet is best, but this is whom I was thinking of.
I have his book on comparing foods by what they told you and what they didn't tell you about them. It's great and sometimes disappointing but an important view and often good to know.
It's called
The Christian's Guide to Natural Products & Remedies: 1100 Herbs, Vitamins, Minerals, Supplements and More!