He's probably referring to the food pyramid, in which those food groups were put forth as foundational building blocks of a healthy diet according to the USDA.

He's probably referring to the food pyramid, in which those food groups were put forth as foundational building blocks of a healthy diet according to the USDA. [1] That saga overlapped with the sugar lobby blaming fats for heart issues [2], and using their weight with the FDA to keep % Daily Values for sugars off food labels until very recently. [3] [1] https://pubmed.ncbi.nlm.nih.gov/8375951/ https://pubmed.ncbi.nlm.nih.gov/8375951/ [2] https://www.npr.org/sections/thetwo-way/2016/09/13/493739074/50-years-ago-sugar-industry-quietly-paid-scientists-to-point-blame-at-fat https://www.npr.org/sections/thetwo-way/2016/09/13/493739074... [3] https://www.vox.com/2016/5/20/11719796/new-nutrition-label-added-sugar https://www.vox.com/2016/5/20/11719796/new-nutrition-label-a...