The human element can serve to add trust in the place of verification, but shouldn't take its place.

People lie. Industry "standards" change commonly accepted definitions. People buy what's cheap, and effective even if it may not exactly be what's on the tin (e.g. farmer buys an 'organic' fertilizer which isn't, thus 'contaminating' the organic nature of the goods going to your table).

That said, I don't see why higher yield with lower nutrition goods are bad in general. It seems malnutrition is from people not eating enough, not from being stuffed with poorly nourishing food.