Table 1:

Each phase of a physical activity and nutrition intervention study and the various issues associated with that phase as it relates to the COVID-19 pandemic

Phase of intervention	Issue related to the COVID-19 pandemic
Recruitment	Contacting potential participants when in-person contact is ill advised and strategies such as recruitment flyers are less effective due to stay-at-home orders. Lack of trust in the scientific community. Ethical concerns with interacting with people during a pandemic, especially vulnerable populations, and those with comorbid conditions, such as obesity. Difficulty generating interest in physical activity and nutrition during a time when more fundamental needs are unmet.
Assessment	University regulations restricting in-person assessments. Creating safe environments for participants to come to assessments. Development of remote assessment methods. Adjusting assessment protocols to minimize in-person contact. Removing collection of physiological variables and biological samples.
Intervention	Closure of sites targeted for intervention delivery. Conversion of face-to-face interventions to online formats (which may decrease intervention fidelity).
Retention	Engagement with the intervention during a time of high stress and competing demands. Loss of employment, phone service, or housing.