Obese women show greater delay discounting than healthy-weight women

Abstract

Delay discounting (DD) is a measure of the degree to which an individual is driven by immediate gratification vs. the prospect of larger, but delayed, rewards. Because of hypothesized parallels between drug addiction and obesity, and reports of increased delay discounting in drug-dependent individuals, we hypothesized that obese individuals would show higher rates of discounting than controls. Obese and healthy-weight age-matched participants of both sexes completed two versions of a DD of money task, allowing us to calculate how subjective value of $1000 or $50,000 declined as delay until hypothetical delivery increased from 2 weeks to 10 years. On both tasks, obese women (N=29) showed greater delay discounting than control women did (N=26; P values <.02). Subsequent analyses showed that these differences were not related to differences in IQ or income. Obese (N=19) and healthy-weight (N=21) men did not differ significantly. Further research is needed to determine why greater delay discounting was not also observed in obese men.