The future is now: comparing the effect of episodic future thinking on impulsivity in lean and obese individuals

The choice of small immediate rewards as opposed to larger delayed rewards, or delay discounting, is an important dimension of impulsive decision making. The inability to delay gratification is related to obesity, as well as other maladaptive behaviors such as substance abuse, problem drinking, smoking, pathological gambling, and risky HIV behaviors. One way to reduce delay discounting (DD) may be to use prospective imagery in the form of episodic future thinking (EFT) during inter-temporal decision making. We have recently shown that EFT reduces DD and ad libitum energy intake in obese individuals. However, no studies have examined whether the magnitude of the EFT effect differs between lean and overweight/obese individuals. We conducted a within-subject design experiment to compare the efficacy of EFT versus a control task in reducing DD between lean (N=24) and overweight/obese (N=24) women. Participants attended two sessions in which they engaged in either EFT or control episodic thinking during a DD task. We also examined whether individual differences such as trait time perspective, behavioral inhibition or behavioral activation moderated the EFT effect on DD. Results showed EFT reduced DD similarly for lean and overweight/obese individuals. The EFT effect was moderated by behavioral activation. This suggests EFT is just as effective in reducing impulsive decision making in obese individuals as it is in lean individuals and may be useful in reducing other impulsive obesity related behaviors.