by Reed Mangels, PhD, RD
In 2019 a group of scientists from 16 countries worked together to propose a healthy dietary pattern that they believed would reduce greenhouse gas emissions by 50% in 2050 and that could feed the global population sustainably. The diet that they proposed emphasized plant foods, including whole grains, vegetables, fruits, nuts, legumes, and unsaturated plant oils; called for low to moderate amounts of animal-based foods; and recommended low intakes of saturated fat, refined grains, and sugar. This diet was called the EAT-Lancet diet (1). A Planetary Health Diet Index has been developed to evaluate how closely people follow the EAT-Lancet diet.
What is the study?
Researchers wanted to see if people who more closely followed the EAT-Lancet diet did better health-wise than those who did not follow the guidelines of this way of eating (2). Almost 160,000 women and 45,000 men who did not have diabetes, cancer, or major cardiovascular diseases at the start of the study completed questionnaires about their eating habits every 4 years. Their reports of what they ate were evaluated using the Planetary Health Diet Index. The total possible Planetary Health Diet Index score ranged from 0 (nonadherence) to 140 (perfect adherence). Deaths among the study subjects were tracked for up to 34 years and were correlated with each subject’s Planetary Health Diet Index score.
What did this study find?
Subjects in the group with the highest score on the Planetary Health Diet Index had the lowest risk of dying from cardiovascular diseases, cancer, respiratory diseases, and neurodegenerative diseases. In women, a higher Planetary Health Diet Index score was also associated with a lower risk of dying from an infectious disease. Eating higher amounts of red and processed meats, eggs, saturated fats, added sugars, sugar from fruit juice, and potatoes was associated with an increased risk of mortality overall.
Based on an environmental analysis, the food choices of the group with the highest Planetary Health Diet Index score resulted in 29% lower greenhouse gas emissions, 21% lower fertilizer needs, 51% lower cropland use, and 13% lower irrigation water needs compared to the group with the lowest score.
The results of this study suggest that choosing a more environmentally friendly diet also promotes lower risk of death from a number of chronic diseases. It’s not surprising that the environmentally friendly diet consists largely of whole plant foods.
To read more about diet and the environment see the environment section of VRG’s website
References
- Willett W, Rockström J, Loken B, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet. 2019;393(10170):447-492.
- Bui LP, Pham TT, Wang F, et al. Planetary Health Diet Index and risk of total and cause-specific mortality in three prospective cohorts. Am J Clin Nutr. 2024 [in press].