Life Expectancy Gains from Dietary Modifications: A Comparative Modelling Study in Seven Countries.

BACKGROUND: Eating healthier is associated with a range of favorable health outcomes. Our previous model estimated the impact of dietary changes on life expectancy gains, but did not consider height, weight, or physical activity.

OBJECTIVE: We estimate the increase in life expectancy resulting from the transition from typical national dietary patterns to longevity-optimizing dietary changes, more feasible dietary modifications, and optimized vegan dietary changes for China, France, Germany, Iran, Norway, the United Kingdom, and the United States.

METHODS: Our modeling study uses data from meta-analyses presenting dose-response relationships between intake of fifteen food groups and mortality. Background mortality data are from the Global Burden of Disease study. We use national food intake data and adjust for height, weight, and physical activity level.

RESULTS: For 40-year-olds, estimated life expectancy gains ranged from 6.2 years (with uncertainty intervals 5.7;7.5) for Chinese females to 9.7 years (8.1;11.3) for US males following sustained changes from typical country-specific dietary patterns to longevity-optimized dietary changes, and from 5.2 years (4.0;6.5) for Chinese females to 8.7 years (7.1;10.3) for US males following changes to an optimized vegan dietary changes.

CONCLUSION: A sustained change from country-specific typical dietary pattern patterns to longevity-optimized dietary changes, more feasible dietary changes, or optimized vegan dietary changes, are all projected to result in substantial life expectancy gains across ages and countries. These changes included more whole grains, legumes, and nuts, and less red/processed meats and sugars and sugar-sweetened beverages. The largest gains from dietary changes would be in the United States.