Misunderstood Menu Metrics: Side-Length Food Sizing Leads to Quantity Underestimation and Overeating

This research highlights consumers’ failure to understand food sizing communicated using side-length metrics (e.g., 12-inch pizza, 8-inch cake, 2-inch cookie), which are ubiquitous in menus and online interfaces. A series of studies show that describing food size options using side-length metrics leads to food quantity underestimation and food intakes misaligned with consumers’ objectives. This robust effect arises because of a linearization heuristic where people do not adequately adjust for the exponential difference in the surface area associated with linear changes in side-length metrics. Choice architecture interventions that replace side-length information with metrics varying linearly with quantities (e.g., surface area, numbers of servings) and training interventions that improve understanding of surface area computation reduce this bias. These findings offer important public policy implications for better food quantity choices by supporting the removal of side-length metrics from the food decision environment.