Expert bodies recommend that populations adopt plant-rich dietary patterns and consume less red and processed meats (RPM) as a high-impact climate action. This PhD dissertation describes three studies that examined how diverse food and health systems actors may encourage sustainable diet transitions for Americans to support human and planetary health. Study one examined U.S. adults' perceptions, beliefs, and behaviors toward plant-rich dietary patterns. The International Food Information Council's Food and Health Surveys (2012–2022) were analyzed using crosstabulation and chi-square analyses. Consumers' recent RPM intake trends were mixed. Despite interest in sustainable products and principles, few U.S. adults followed plant-rich dietary patterns or purchasing practices. Leadership and coordinated action are needed to incentivize Americans to adopt plant-rich dietary behaviors. Study two conducted a systematic scoping review of media campaigns that promoted plant-rich dietary patterns and traditional and novel plant-based proteins, and that encouraged or discouraged RPM products to Americans (1917-2023). Of 84 media campaigns identified, corporate marketing (58.6%) campaigns were most prevalent compared to public information (13.8%), corporate sustainability (12.6%), countermarketing (5.7%), social marketing (4.6%), and public policy (4.6%). Civil society campaigns promoted plant-rich dietary patterns, but only one campaign was evaluated. U.S. government, academia, businesses, and civil society should commit adequate resources and evaluate media campaigns to support a sustainable diet transition for Americans that prioritizes traditional and novel plant-based proteins. Study three explored U.S. Food is Medicine (FIM) experts' views on how plant-rich dietary patterns and other sustainable diet practices could be incorporated into FIM interventions. Twenty semi-structured interviews were conducted among U.S. food and health systems actors and analyzed using inductive and deductive thematic analysis. Results indicated that many FIM actions support human and planetary health, but the co-benefits are not often discussed. The FIM movement is a unique opportunity to promote food and health systems changes that support human and planetary health, but key challenges require coordinated action across sectors. The three studies in this PhD dissertation collectively addressed knowledge gaps, used novel conceptual frameworks, and offered recommendations to inform U.S. food and nutrition policies, programs, and research to encourage sustainable diet transitions for American adults. / Doctor of Philosophy / Expert bodies recommend that populations adopt plant-rich dietary patterns, or ways of eating that emphasize intake of plant-based foods (i.e., whole grains, fruits, vegetables, legumes, nuts, and seeds) and de-emphasize or avoid intake of animal-sourced foods, especially red and processed meats (RPM). Plant-rich dietary patterns can reduce diet-related disease risks and minimize the food system's negative environmental contributions. This PhD dissertation describes three studies that examined how diverse food and health systems actors may encourage Americans to transition towards plant-rich dietary patterns and reduce RPM intake to support human and planetary health. Study one analyzed 11 years of survey data (2012–2022) to examine U.S. adults' perceptions, beliefs, and behaviors toward plant-rich dietary patterns. Consumers' recent RPM intake trends were mixed, with some reporting increased consumption and others reporting reduced RPM intake. Few adults reported adherence to plant-rich dietary patterns. Leadership and coordinated action are needed to incentivize Americans to adopt plant-rich dietary behaviors. Study two reviewed published literature to identify the landscape of media campaigns that promoted plant-rich dietary patterns and plant-based proteins, and that encouraged or discouraged RPM products to Americans (1917-2023). Of 84 media campaigns identified, most (58.6%) campaigns promoted specific food products. Only one campaign was evaluated. U.S. government, academia, businesses, and civil society should commit adequate resources and evaluate media campaigns that promote plant-rich dietary patterns and plant-based food products. Study three explored U.S. Food is Medicine (FIM) experts' views on how plant-rich dietary patterns and other sustainable diet practices could be incorporated into FIM interventions, which aim to connect food to the health system. Twenty interviews were conducted among U.S. food and health systems actors and analyzed for key themes. Results indicated that many FIM actions support human health and the environment, but the co-benefits are not often discussed. The FIM movement is a unique opportunity to promote food and health systems changes that support human health and environmental sustainability, but key challenges require coordinated action across sectors. These three studies help inform how food and health systems actors can support Americans to adopt dietary practices that promote human health and the environment.

The Patient Protection and Affordable Care Act (PPACA) of 2010 requires hospital systems in the United States to shift the culture of patient care from a focus on sick-care to a focus on prevention and wellness care. Little is known about how hospital systems will make this culture shift while retaining quality patient care. The purpose of this case study of a pioneering hospital-based PPACA-compliant initiative was to answer the research question of how Wallace's revitalization movement theory (RMT) "a rapid culture change model"could serve as a transferable evaluation framework for PPACA prevention and wellness care compliance in hospital-based programs. Kingdon's policy streams theory provided a conceptual framework. Data analysis included iterative, thematic coding of interviews with 3 primary stakeholders responsible for developing the policy, planning, and program implementation strategies of the Center for Total Health (CTH). Nineteen extensive primary source documents were included in the analysis as well. Findings supported the utility of the RMT structure and definitions in the identification of culture change dynamics in CTH. Additionally, this structure served as a scaffolding for grouping individual and institutional rapid culture change dynamics into stages that could be evaluated in terms of PPACA compliance. These stages effectively identified a Kingdon policy window in which PPACA mandates could be expected to result in culture change in multiple streams of public policy development, not only in wellness and sickness prevention, but also in local, state, and national health cost-saving initiatives in food-as-medicine, community identity, public health support networks. It could also reduce chronic disease and the rising institutional care delivery costs.