Studies of persons in treatment for substance use disorder (SUD) frequently report significant body weight gain and higher food consumption. It is unclear what psychological variables might mediate a relationship between SUD treatment status and food selection. To examine the association between SUD treatment status and food selection, 212 men and women (104 in treatment for SUD) were asked, in an online survey, to choose from among 16 food images in an imagined all-you-can-eat buffet scenario. Food craving, emotional eating (EE), impulsivity, and drugs used were examined as potential mediators while reward responsiveness (RR) was examined as a potential moderator. The amount of energy from foods selected was the predicted variable. Results indicated that those in treatment for SUD had significantly higher food cravings, positive EE, and attentional and motor impulsivity (but not RR or negative EE) which were (with the exception of RR) not correlated with energy selected from food images. Those in SUD treatment selected more energy (M = 2655.10 kcal, SEM = 156.97) from food images than those in the control group (M = 2221.52 kcal, SEM = 112.29), t(188) = -2.25, p = 0.026. In a multiple regression moderation analysis, SUD treatment status (β = 419.58, p = 0.029) and RR (β = 39.23, p = 0.016) were significant predictors of energy from foods selected. The amount of energy selected from food images predicted by SUD treatment status was dependent on values of RR. Mean BMI was not significantly higher for the SUD group but there were more participants with BMI values over 29 and fewer with BMI between 25 and 29 in the SUD treatment group. While the cause remains unclear, the results show that persons in treatment for SUD and with higher RR do select more energy from food images in a meal scenario.