Is obesity caused by calorie underestimation? A psychophysical model of meal size estimation

Calorie underestimation is often alleged to contribute to obesity. By developing a psychophysical model of meal size estimation, the authors show that the association between body mass and calorie underestimation found in health science research is a spurious consequence of the tendency of high-body-mass people to choose-and thus estimate-larger meals. In four studies involving consumers and dieticians, the authors find that the calorie estimations of high- and low-body-mass people follow the same compressive power function; that is, they exhibit the same diminishing sensitivity to meal size changes as the size of the meal increases. The authors also find that using a piecemeal decomposition improves calorie estimation and leads people to choose smaller, but equally satisfying, fast-food meals. The findings that biases in calorie estimation are caused by meal size and not body size have important implications for allegations against the food industry and for the clinical treatment of obesity.