A new study suggests that adopting a diet rich in minimally processed plant foods not only benefits individual health but also contributes positively to environmental sustainability. The research, published in the American Journal of Clinical Nutrition, found that diets primarily consisting of nuts, beans, fruits, vegetables, whole grains, and olive oil, along with moderate amounts of meat, fish, eggs, and dairy, are linked to lower rates of premature death from heart disease, cancer, and other chronic conditions. Additionally, these diets have a smaller environmental footprint, as they involve foods grown using relatively less land and water and produced with fewer greenhouse gas emissions.
Background
Asthma is a chronic inflammatory disease with genetic and environmental factors. Globally, asthma’s burden on patients and healthcare systems is increasing, causing about 15 million disability-adjusted life years lost annually. Around 300 million people have asthma, with prevalence rising. Though more common in high-income countries, low-income countries are also affected. Childhood asthma prevalence is 10.1% in Brazil, 5.35% in India, 10.6% in Oman, and 6% in Iran. Risk factors include no breastfeeding, socioeconomic status, infections, and dietary intake. Further research is needed to confirm the relationship between a Western dietary pattern and childhood asthma, particularly in the Middle East, where dietary habits are rapidly changing.
The Study and Its Findings
The study, inspired by the EAT-Lancet Commission’s 2019 “Planetary Health Diet,” analyzed data from over 200,000 men and women in the United States over three decades. The Planetary Health Diet is designed to sustain both human and planetary health by 2050, emphasizing increased consumption of plant-based foods and smaller portions of meat and dairy. The new study’s key findings include:
Lower Mortality Risk: Individuals whose diets closely followed the Planetary Health Diet had a 30% lower risk of premature death compared to those with the lowest adherence to the diet.
Reduced Illness: Adherence to the diet was associated with a 10% lower risk of cancer mortality, a 14% lower risk of cardiovascular death, a 47% reduction in lung disease mortality, and a 28% lower risk of dying from Alzheimer’s disease and other neurodegenerative conditions.
Lower Infectious-Disease Risk: Women adhering closely to the diet had a 38% lower risk of dying from infectious diseases.
Environmental Benefits: The diet was linked to a 29% reduction in greenhouse gas emissions, a 51% decrease in cropland use, a 21% reduction in fertilizer use, and 13% lower irrigation and water needs.
How to Follow a Planetary Health Diet
Participants in the study who adhered closely to the Planetary Health Diet consumed large amounts of:
Whole fruits and non-starchy vegetables such as carrots, broccoli, asparagus, cauliflower, cucumber, and leafy greens.
Peanuts and tree nuts such as walnuts, hazelnuts, pecans, cashews, and pistachios.
Legumes such as beans, lentils, and peas.
Chicken and other forms of poultry.
Foods rich in unsaturated fats like avocados, olive oil, and sunflower oil.
Whole grains such as brown rice, wild rice, oatmeal, quinoa, and barley, along with whole-grain foods like whole wheat bread and rye bread.
Lower amounts of red and processed meats, eggs, soft drinks, fruit juices, and sugary processed foods, including candy, cakes, breakfast cereals, and desserts.
Walter Willett, a senior author of the study and a professor at the Harvard T.H. Chan School of Public Health, emphasized that the diet does not require giving up meat. It allows for two servings of animal foods per day, including dairy, red meat, eggs, poultry, and fish, making it adaptable to various cultural and culinary preferences.
How Healthy Eating Slows Climate Change
Food production is responsible for about 30% of global greenhouse gas emissions, driven largely by livestock methane emissions, deforestation, and agricultural practices. In the U.S., most cropland is used to grow corn and soy for livestock feed, which degrades soil, reduces biodiversity, and requires extensive irrigation and chemical use. Only about 5% of farmland grows vegetables, fruits, nuts, and legumes.
Changing dietary habits and food production practices alone won’t stop climate change, but they are significant steps. Willett noted that shifting to healthier diets can substantially impact climate change, demonstrating that human and planetary health can improve together—a “double win.”
Policy Implications and Future Directions
The study was observational, meaning it found correlations rather than direct causation. Researchers accounted for various lifestyle factors, such as smoking, exercise, alcohol consumption, and family histories of disease. The health benefits of diets rich in nuts, olive oil, whole grains, fruits, and vegetables have been corroborated by rigorous clinical trials.
Marion Nestle, an emeritus professor of nutrition at NYU, advocates for government policies that promote nutritious and sustainable diets. She suggests clear dietary guidelines, healthier school meal standards, support for food production for human consumption, and reduced subsidies for industrial meat production.
Conclusion
This groundbreaking study reinforces the idea that what is beneficial for individual health can also be advantageous for the environment. By adopting the Planetary Health Diet, individuals can enjoy a reduced risk of chronic diseases and contribute to a more sustainable future. As dietary habits evolve, the potential for significant improvements in both public health and environmental sustainability becomes increasingly clear.