Why Nutrition Science is Essential for Healthcare and Planetary Health

We are what we eat, but so is the Earth. Every morsel and meal contributes to our climate footprint, and diets often focus on food that’s bad for us and nature. It’s time to plate-up something different. Current dietary patterns are damaging our health and that of the planet. Poor diets are responsible for an estimated 20-25% of all adult deaths. At the same time, food is the largest driver of planetary boundary transgressions, exerting pressure on climate stability, ecosystems, land, and water resources beyond safe limits for humanity. Notably, food systems account for one-third of total greenhouse gas emissions, driving climate change, which also has substantial impacts on human health and food availability. These challenges are interlinked. Improving diet quality can reduce the burden of diseases, including cardiovascular diseases, type 2 diabetes, obesity and related metabolic complications, potentially preventing up to 15 million premature deaths per year. Evidence also indicates that shifting to healthy diets would change food demand, which could reduce food-related greenhouse gas emissions by 30-50%, land use by 45-70%, water use by 25-35%, and eutrophication potential by 35-55%. Despite this compelling evidence, health systems worldwide undervalue nutrition as a core component of prevention, care, or environmental responsibility. Integrating nutrition into medical practice is therefore not a lifestyle intervention, but a necessary response to rising health and environmental crises. Nutrition is key to human and planetary health The food we eat is not just a matter of personal choice. It is a major driver of environmental change. Current food systems are failing both people and the planet. From a health perspective, one-in-11 people globally are undernourished, while millions more live with preventable diet-related chronic diseases. Noncommunicable diseases remain the leading cause of death and disability worldwide. For instance, in 1990, diabetes ranked as the 20th leading cause of global disease burden, today it ranks 5th, reflecting both increased prevalence and growing metabolic risk worldwide. In 2021, type-2 diabetes accounted for 96% of all diabetes cases, where unhealthy diet is a major risk factor, making nutrition a central part of chronic disease management. Environmentally, rising demand for resource-intensive foods, particularly higher consumption of meat and dairy in many high-income settings, is accelerating deforestation, ecosystem loss, and climate change. Forests and other landscapes, particularly in the vital Amazon Basin, are being cut down for farmland on which to graze cattle or grow livestock fodder, like soy. Notably, beef production alone accounts for 41% of global deforestation, which, in turn, is a key driver of global warming. Beef and mutton can have up to 100 times the emissions per weight than plant-based foods like vegetables, fruits, legumes, and grains. These dynamics reinforce one another. Environmental degradation undermines food production, while climate change exacerbates undernutrition, food price volatility, and diet-related disease. Stable climate, fertile soils, freshwater availability, and biodiversity are therefore part of the foundations of public health, and protecting these life-support systems is fundamental to strengthening public health. Physicians can lead food system transformation – in the clinic and beyond Despite the central role of diet in shaping health outcomes, nutrition remains marginal in medical education and practice worldwide. Many physicians receive little formal training in nutrition, leaving them underprepared to address diet as a clinical risk factor or prevention tool. For example, a study in the UK found that 70% of physicians reported receiving less than two hours of nutrition education at medical school. This lack of training is mirrored in healthcare settings themselves. Hospitals and other health institutions frequently serve meals that do not align with evidence-based dietary recommendations, undermining prevention efforts and sending contradictory signals to patients and staff alike. Yet, physicians, particularly general practitioners, are uniquely positioned to drive dietary change. They are among the most trusted professionals in society, and often the primary point of contact for discussions about diet, especially where access to dietitians or nutritionists is limited. By integrating nutrition science into routine care, physicians can strengthen prevention where it matters most: in everyday clinical encounters. Framing dietary advice around health and environmental co-benefits, such as reduced cardiovascular risk alongside lower environmental impact, can make guidance more relevant and actionable without adding complexity. Beyond the clinic, physicians also play influential roles within institutions and health systems. They can help shape hospital and institutional food environments, contribute to curriculum reform, inform clinical guidelines, and support policies that align healthcare delivery with contemporary nutrition and sustainability science. Practical framework for physicians to lead the change The Planetary Health Diet, developed by the 2025 EAT-Lancet Commission, provides a science-based framework for aligning human health with environmental sustainability. The diet emphasises wholegrains, fruits, vegetables, legumes, nuts, and unsaturated fats, with modest amounts of animal-source foods. Analyses indicate that this diet, rich in plants and low in animal-products, is also environmentally sustainable. To support healthcare professionals in translating this evidence into practice, the Physicians Association for Nutrition (PAN International), in partnership with EAT, convened a dialogue series of more than 70 healthcare organisations to co-develop an Action Brief for Healthcare Professionals. The Brief outlines practical steps to embed nutrition into clinical practice and education, promote prevention, and mobilise healthcare professionals as leaders in food system transformation. To drive a population-wide shift towards healthier, more sustainable diets, the Action Brief includes clear, evidence-based guidance organised around three pillars: * Actions to implement – embedding nutrition in clinical practice and education, promoting prevention, and mobilising healthcare professionals as food system advocates. * Actions to stop or change – moving beyond nutrient tunnel vision, improving hospital food environments, and tackling both under- and over-nutrition together *Unlocks for collaboration – engaging policymakers, hospitals, catering staff and educators to remove barriers Strategies will differ across contexts. In many high-income countries, priorities may include reducing excessive consumption of meat and ultra-processed foods. In other settings, the focus may be on improving dietary diversity, addressing undernutrition, or preventing rapid dietary transitions. Nutrition science provides the tools to tailor solutions without losing sight of shared planetary constraints. Integrating nutritional science into medical practice Empowering healthcare professionals to promote diets that are healthy for people and sustainable for the planet, offers an important opportunity to address diet-related diseases and environmental degradation. What we eat, and how healthcare professionals guide those choices, can shape the future of both people and the planet. Sumati Bajaj, is Nutrition Knowledge Specialist at the Physicians Association for Nutrition (PAN International). Image: Eiliv Aceron / Unsplash More Case Studies, Features & Industry Insight: A guide to using AI for Environmental Impact Assessments