Planetary Health Diet Tied to Decreased Risk of Premature Death, Study Finds

According to a new study led by Harvard T.H. Chan School of Public Health, people who eat a healthy, sustainable diet may substantially lower their risk of premature death in addition to their environmental impact.

The study was published in The American Journal of Clinical Nutrition.

The Planetary Health Diet, designed to promote both human health and environmental sustainability, has been linked to a lower risk of premature death. This diet emphasizes a balanced intake of plant-based foods, including fruits, vegetables, whole grains, nuts, and legumes, while limiting red meat, processed foods, and added sugars. By focusing on nutrient-rich, minimally processed foods, the Planetary Health Diet helps reduce the risk of chronic diseases such as heart disease, diabetes, and certain cancers.

The diet's high fiber content aids in maintaining healthy digestion and stable blood sugar levels, while its emphasis on healthy fats from sources like nuts and seeds supports cardiovascular health.

While other studies have found that diets emphasizing plant-based foods over animal-sourced foods could have benefits for human and planetary health, most have used one-time dietary assessments, which produce weaker results than looking at diets over a long period of time.

In the study, researchers used health data from more than 200,000 participants who were free of major chronic diseases at the start of the study and completed dietary questionnaires every four years for up to 34 years. Participants’ diets were scored based on intake of 15 food groups—including whole grains, vegetables, poultry, and nuts—to quantify adherence to the PHD.

The results revealed that:

1. People whose diets most closely adhered to the Planetary Health Diet (PHD) had 30% lower risk of premature death compared to those with the lowest adherence.

2. Every major cause of death, including cancer, heart disease, and lung disease, was lower with greater adherence to this dietary pattern.

3. Diets adhering to the PHD pattern had substantially lower environmental impact, including 29% lower greenhouse gas emissions and 51% less land use.

Reference: Planetary Health Diet Index and risk of total and cause specific mortality in three prospective cohorts,” Linh P. Bui, Tung T. Pham, Fenglei Wang, Boyang Chai, Qi Sun, Frank B. Hu, Kyu Ha Lee, Marta Guasch-Ferre, Walter C. Willett, The American Journal of Clinical Nutrition, June 10, 2024, doi: 10.1016/j.ajcnut.2024.03.019