Objectives: Cross-sectional reports on weight gain during the COVID-19 shelter-at-home have raised concerns for weight increases as the pandemic continues. We examined behaviors that impact energy intake and/or energy expenditure among adults in the United States during shelter-at-home. Methods: Cross-sectional data (N=1779; April 24 - May4, 2020) were collected on demographics, diet, physical activity, sleep, and food purchasing behaviors. Percent of participants reporting increase/ decrease/no change in these behaviors during the COVID-19 shelter-at-home were assessed. Each analysis was followed by comparing whether increases or decreases were more likely for each health behavior, in all participants and across sex (43.38% males). Results: Increased consumption of healthy foods, energy-dense unhealthy foods, and snacks, and increased sedentary activities (p < .001) was reported. Physical activity and alcohol intake declined (p < .001). Females were more likely than males (p < .001) to report ultra-processed foods/high-calorie snack intake, fruit/vegetable intake (p < .001) and increase (p < .01) sleep and sedentary behavior. Conclusion: Acute behavioral changes supporting greater energy intake and less energy expenditure, especially in females, underscore the significance of COVID-19-related increase in unstructured time. Longitudinal assessment of body weight and health behaviors is warranted to understand the impact of pandemic.