Objective: Several environmental factors contribute to increased food consumption and play a role in the prevalence of obesity, like portion size, accessibility and relative price of high caloric foods, food commercials and sales promotions. However, not everyone seems equally sensitive to these environmental cues and both obesity and impulsivity appears to play a role. Design and Methods: In the present study, food purchases in an internet supermarket are tested in 118 participants, with or without sales promotions for snack foods. Both weight status and response inhibition, an index of impulsivity, are measured. Results: Participants with less inhibitory control purchased in total more calories from the internet supermarket then participants with more inhibitory control. In addition, sales promotion, weight status and inhibitory control appeared to interact in their effect on snack food purchases: participants with less inhibitory control and overweight bought more calories of snacks in the sales promotions condition, but not in the control condition. For the other participants, with normal weight and / or high inhibitory control, sales promotions had no effect on their purchases of calories of snacks. Conclusions: It seems that especially the combination of low inhibitory control and overweight makes participants vulnerable for environmental cues.