Energy balance

Rising obesity in developed countries is primarily driven by increased caloric intake (energy in) rather than reduced physical activity (energy out).

To manage weight in the modern developed world, focus on reducing caloric intake. The evidence suggests that increased food availability, lower food prices, and sociodemographic shifts (like urbanization and female labor force participation) have driven up calorie consumption, which is the main driver of obesity. While physical activity is important for health, it is not the primary factor driving the obesity epidemic; therefore, dietary changes are the most effective intervention for weight loss.