COVID-19 has severely impacted population health and well-being globally. Acknowledging that COVID-19 will not be the world's last pandemic, improving healthy living factors (i.e., physical activity, healthful nutrition, healthy weight), which are important in mitigating negative outcomes of future infectious disease pandemics, should be prioritized. Although well-documented, promoting healthy living factors remains challenged by a lack of scalability and sustainability due, in part, to a mismatch between intervention focus on individual behavior change as opposed to recognizing complex and multifactorial causes that prevent people from living healthy lifestyles and maintaining them long-term (such as political will, economic benefits, urban planning, etc.). To recognize this complexity in promoting healthy living, we propose the application of systems science methods for the creation of a comprehensive causal systems map of healthy living factors in the context of COVID-19 to inform future pandemic preparedness. Generating such a map would benefit researchers, practitioners, and policy makers in multi-sector collaborative efforts to improve public health preparedness in the context of future pandemics in a scalable, sustainable, and equitable manner. This effort should be facilitated by a trusted and widely respected governing body with global reach.