Impatience and Present Bias Do Not Determine Weight Loss in Obesity: Evidence From Lab‐in‐Field and Survey Data

A substantial body of behavioral economics literature links obesity to time preferences, notably impatience-a time-consistent preference for earlier rewards-and present bias-the disproportionate overweighting of immediate payoffs that leads to dynamic inconsistency. Unlike much previous literature, which asks whether time preferences predict weight in broader populations, we examine whether they predict subsequent weight loss among adults who already have overweight or obesity. Using clinically measured outcomes and incentivized preference data from 287 adults with obesity and pre-diabetes enrolled in a 12-month randomized lifestyle-intervention trial, we find that neither impatience nor present bias predicts reductions in body fat or BMI. These findings are robust to alternative measurement strategies and are not explained by the impatience-related attrition that we uncover. To strengthen external validity, we replicate the null relationship using self-reported time preference measures in a nationally representative sample of 7277 adults with overweight or obesity. As baseline impatience meaningfully reduces the likelihood of trial completion, we conclude that impatience affects adherence to medically recommended programs but does not directly impede weight-loss success among those who remain engaged. Interventions targeting impatience or self-control alone may therefore be insufficient to promote weight loss in clinical populations.