Coke vs Pepsi: Why Americans are so fiercely loyal to their soda of choice

Americans’ intense Coke-versus-Pepsi loyalty appears to be shaped by more than just taste. Coca-Cola and Pepsi have small but measurable formulation differences: Pepsi includes citric acid, while Coca-Cola does not, and Pepsi has slightly more sugar per 12-ounce serving (about 41 grams versus Coke’s 39). Beverage Digest reported that Classic Coke led U.S. carbonated soft drink volume in 2025 with an 18.5% share, while Pepsi returned to third at 8.1% after slipping in 2024. A Baylor College of Medicine study using brain scans found brand cues influenced preferences for Coke, with no comparable effect for Pepsi—highlighting marketing and cultural associations.