Scientists do studies that identify specific nutrients and vitamins that are healthy.  That gives agri-business a target to efficiently chase, to the exclusion of all the other benefits of whole food that didn't fit into the study.  

If only that, but I'm afraid the order is reversed ; the industry asks for "this food is healthy" studies to use as marketing. See Popeye produced by the Spinach industry, or the "discovery" that wine is healthy...

Un roi sans divertissement est un homme plein de misères