How dietary changes and lifestyle shifts fueled the American obesity epidemic in the 1980s

American obesity rates sharply increased in the late 1970s and early 1980s due to a confluence of factors. Government dietary guidelines encouraged reduced fat intake, leading food manufacturers to replace fat with sugar and refined starches. Simultaneously, portion sizes grew, and physical activity declined. This period saw a surge in high-fructose corn syrup, increased restaurant dining, and a rise in ultra-processed foods, contributing to a complex environmental shift that fueled the obesity epidemic.