Before the food pyramid came the wartime Basic Seven and the Basic Four, America's first food guides, built to prevent deficiency under rationing rather than chronic disease. The food industry was invited to review them from the start, opening a century-long question of who decides what a country eats.
Sources differ on who simplified the Basic Seven into four groups, USDA or Harvard researchers, and on which guide first gave serving numbers. How far industry shaped the content, rather than just reviewing and promoting it, is not well supported for this early period.