While many diets focus on just food, the Ikigai Diet regards positive thinking to be a main part of the diet because it is a diet to support our intestines. A thought is a vibration. Every thought you have send a vibration to your body, especially to your intestines.
A lot of people around me don’t seem to be happy with the name judging from Facebook comments. If we interpret rei as commands or order, it sounds militaristic like harmony is ordered by the government. Considering the philosophy of our prime minister Abe, it isn’t surprising that he wanted to imply it in the name.