Different people react differently to different foods, even the same food at different times or under different conditions. His remarks there read a bit like some stuff I've read by the proponents of, variously, vegetarian, paleo and keto diets.

I don't eat breakfast, as a rule. I used to get peckish in the mid-morning, now I don't get hungry until lunchtime. Not being hungry helps me concentrate. I hardly see this as the basis of a new way of life.