Eating more fibre-rich foods, less red meat and sugar may prolong life expectancy

Changing your usual eating pattern to one that is focused on longevity can bring substantial increases in life expectancy (LE), suggests a study that involved seven countries. These dietary changes include more whole grains, legumes, and nuts and less red/processed meats, sugars, and sugar-sweetened beverages.

Among the involved countries (ie, China, France, Iran, Germany, Norway, the US, and the UK), the US appears to have the largest LE gains, followed by the UK.

“Higher intakes of legumes, whole grains, and nuts and lower intakes of red and processed meats and sugar-sweetened beverages contributed most to these [LE] gains,” said the researchers.

For individuals aged 40 years, the estimated gains in life expectancy following sustained changes from typical country-specific dietary patterns to longevity-optimized dietary changes ranged from 6.2 years (uncertainty interval [UI], 5.7‒7.5) for Chinese females to 9.7 years (UI, 8.1‒11.3) for US males. [Am J Clin Nutr 2024;120:170-177]

Furthermore, the estimated gains following changes to optimized vegan dietary changes ranged from 5.2 years (UI, 4.0‒6.5) for Chinese females to 8.7 years (UI, 7.1‒10.3) for US males.

“Across all countries and age groups, projected gains in LE are greater for males than for females, which may help to address the current sex-dependent inequality in lifespan in most countries,” the researchers said.

Dietary pattern

The biggest gains in LE are seen with eating more legumes, whole grains, and nuts and consuming less red/processed meats and sugar-sweetened beverages. However, there is a slightly different ranking across countries because of variations in current habitual dietary patterns.

“Thus, although intake of fruits and vegetables is strongly inversely associated with mortality, in most countries, intake of fruits is closer to the optimal level than that of whole grains and legumes, so there is less benefit by further increasing fruit intake,” the researchers said. [Int J Epidemiol 2017;46:1029-1056; Am J Clin Nutr 2017;105:1462-1473]

“It is likely that there will be variation in health outcomes associated with differences in specific foods within each of the food groups and in food processing and preparation methods,” they added.

For instance, using olive oil, which is rich in monounsaturated fatty acids, appears more beneficial than other types of oils. [Cochrane Database Syst Rev 2018;7:CD012345; Lipids Health Dis 2014;13:154; N Engl J Med 2018;378:e34]

In a 2021 study comparing dietary guidelines among 96 countries worldwide, 90 had recommendations on fruits and vegetables, 79 on sugar, 59 on grains/cereals, 58 on fish, 50 on legumes, and only 19 on nuts. This suggests an opportunity to highlight nuts as well as whole grains, fish, and legumes in dietary guidelines. [Trends Food Sci Technol 2021;109:219-229]

The current study used data from meta-analyses presenting dose-response relationships between intake of 15 food groups and mortality. Background mortality data were obtained from the Global Burden of Disease Study. The researchers used national food intake data, adjusted for height, weight, and physical activity level.