Prior research shows that people demonstrate greater regulation of motor and social activities when they are in a confined physical space. This article examines whether space constraint affects people’s behavior toward hedonistic consumption of vice products (e.g., high-calorie foods) and their self-regulation in general. We propose that space constraint may have a generalized effect that enhances regulation of behaviors that are unrelated to the space. Manipulating space constraint by varying density or by assigning individual participants to different-sized rooms, three experiments demonstrated that smaller (vs. larger) spaces reduce impulsive purchase of vice products, lead to lower consumption of high-calorie foods, and yield fewer false alarms in a go/no-go task. Consistent with our findings, both international and US data showed that more densely populated regions have a lower prevalence of outcomes associated with low self-control (e.g., prevalence of overweight and obesity, death caused by road traffic accidents).