After World War II, Kushi studied in Japan with macrobiotic educator, George Ohsawa.

Elizabeth Whelan and Frederick J. Stare have noted that: Kushi's claim that cancer is largely due to his own versions of improper diet, thinking, and lifestyle is entirely without foundation.

In his books, Kushi has recounted numerous case histories of persons whose cancer allegedly disappeared after following a macrobiotic diet.

There are no available statistics on the outcome for all of these patients, but it is documented that at least some of them succumbed to their disease within a relatively short period.

Reported testimonials of remission often uncovered the fact that the patients were also receiving conventional medical treatment at the same time.