The 1992 USDA Food Pyramid promoted a carbohydrate-dominant diet that shaped U.S. nutrition policy, school meal programs, food manufacturing, and eating habits for decades. This article examines its origins, Ancel Keys' influence, its impact on America's food system, and why critics link it to rising obesity, type 2 diabetes, and metabolic disease before its retirement in Spring 2026.

Dr. Ancel Keys helped popularize the belief that saturated fat was the primary cause of heart disease. Critics argue that his Seven Countries Study selectively used data supporting that conclusion. In the 1960s, the Sugar Research Foundation funded Harvard researchers who downplayed sugar's role in heart disease and emphasized dietary fat instead. This influenced decades of low-fat dietary guidelines. Later research renewed scrutiny of these recommendations.