Developing a more nuanced understanding of factors predicting risk of dietary lapse (i.e., instances of non-adherence to a reduced calorie diet) is important, because dietary lapses contribute to suboptimal weight outcomes. The study investigated, for the first time, how various everyday activities affected likelihood of dietary lapses at two timescales—both in-the-moment, and in the hours after engaging in an activity. Participants (N = 107) with overweight/obesity in a behavioral weight loss program completed ecological momentary assessment surveys on dietary adherence and daily activities for 3 weeks at mid-treatment. Generalized estimating equations revealed that socializing predicted greater concurrent lapse risk, while work/school, doing chores, cooking, or practicing a spiritual activity/prayer/meditation were associated with reduced lapse risk. In terms of subsequent effects, cooking and indoor hobbies were associated with greater lapse risk in the next few hours, whereas spiritual activity/meditation was associated with reduced risk. Certain activities may have affected concurrent and subsequent lapse risk due to: their influence on the presence of tempting food, the compatibility of engaging in the activity and eating simultaneously, and the reward reaped from the activity (potentially reducing desire for food-related reward). Findings speak to the importance of attending to the timescale of relationships between activities and lapses, which has clinical implications for providing nuanced and optimally timed interventions for overweight/obesity.