The Health and Environmental Impacts, Safety, and Affordability of the EAT-Lancet Planetary Health Diet: A Multidisciplinary Systematic Review and Meta-Analysis.

In 2019, the EAT-Lancet Commission proposed transition to the planetary health diet, whereas the health and environmental benefits, safety, and affordability of the diet have recently been challenged. This systematic review and meta-analysis aimed to provide a quantitative summary of the EAT-Lancet diet and population health and environmental sustainability; and to review safety (nutrient deficiencies) and affordability of the diet. We searched PubMed, Embase, Web of Science, CINAHL, Cochrane Library, and ClinicalTrials.gov from 1 January 2019 to 19 June 2025 for quantitative studies. Of the eligible studies, epidemiological studies on population health or environmental sustainability were further used for meta-analysis. The risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale tool. A total of 227 studies were included in the systematic review and 79 of them were used for the meta-analysis. Most prospective cohort studies and half the cross-sectional studies were of high quality. The EAT-Lancet diet was associated with lower risks of all-cause mortality [pooled hazard ratio = 0.80, 95% confidence interval (CI): 0.76, 0.85; n = 17, 1,063,289 participants], cardiovascular disease (0.83, 95% CI: 0.74, 0.94; n = 10, 1,027,822 participants), and type 2 diabetes, but not risks of all cancers or dementia. The EAT-Lancet diet was associated with a reduction of 1.55 (0.22, 2.89) kg CO2 eq/d/person of greenhouse gas emission (n = 12, 882,673 participants), whereas no strong evidence supported the benefits to water or land use. On a global average, the EAT-Lancet diet would induce deficiencies in vitamin B12, calcium, iron, and zinc in adults, especially in pregnant women. Globally, 1.6-3.0 billion people were not able to afford the diet. In conclusion, adoption of the EAT-Lancet diet may modestly reduce global chronic disease and environmental burden, whereas nutrient deficiencies and economic inequality across regions should be addressed before dietary transition. TRIAL REGISTRATION NUMBER: This study was registered at PROSPERO as CRD42024540867 (URL of registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42024540867).