<ns3:p><ns3:underline>Background </ns3:underline></ns3:p><ns3:p> Integrated metrics that account for resource use and human health are essential to help identify and support human development pathways that safeguard planetary health. We identify countries that achieved the highest levels of health and development at the lowest cost to Earth’s natural capital and report ecological within-country analyses of associations between indicators of environmental sustainability, human health, and development.</ns3:p><ns3:p> <ns3:underline>Methods </ns3:underline></ns3:p><ns3:p> We used mixed-effects multiple linear regression models of Healthy Life Expectancy (HALE) and Human Capital (HC) related to Ecological Footprint (EF) and CO<ns3:sub>2</ns3:sub> production emissions, controlling for Gini coefficient and population density applied to data of 216 countries from 1991-2016. We performed stratified analyses by country income level and used likelihood-ratio tests to test for interaction.</ns3:p><ns3:p> <ns3:underline>Results</ns3:underline></ns3:p><ns3:p> Only Jamaica (1991) and Sri Lanka (2016) achieved high HALE at sustainable EF levels. Each 10% increase in EF was associated with 0·20 (95%CI 0·16,0·24) and 0·21 (95%CI 0·19,0·23) increases in HALE and HC respectively; increases in CO<ns3:sub>2</ns3:sub> production emissions were also associated with increased HALE and HC. There was strong evidence for interaction by income level for each model (p&lt;0·016). Stratified analyses showed that in high income nations HALE and HC decreased with increased levels of EF and CO<ns3:sub>2</ns3:sub>.</ns3:p><ns3:p> <ns3:underline>Conclusions </ns3:underline></ns3:p><ns3:p> Countries with high health metrics at sustainable EF levels may offer valuable lessons for sustainable national development policies. Increased environmental footprint and CO<ns3:sub>2</ns3:sub> emissions appear associated with higher levels of human health and development only up to a certain level of income.</ns3:p>