New research is showcasing how a more healthy, balanced diet — including more legumes, whole grains, and nuts, while cutting down on red and processed meat — can lead to longer lives.

“You are what you eat” is an age-old saying, but a new study from the University of Bergen says that we also live as long as what we eat. The healthier and more diverse our diets, the healthier and longer our life expectancy (LE) becomes, it reports.

The paper estimates the effect of such changes in the typical Western diets for the two sexes at various ages; the earlier these guidelines are incorporated into our eating habits, the larger the improvements in LE, but older people stand to benefit from significant (if smaller) gains as well.

Change your meals, enjoy more meals

“Our modeling methodology used data from [the] most comprehensive meta-analyses, data from the Global Burden of Disease study, life-table methodology, and added analyses on [the] delay of effects and combination of effects including potential effect overlap”, says Lars Fadnes, a Professor at the Department of Global Public Health at the University of Bergen who led the research, in an email for ZME Science.

“The methodology provides population estimates under given assumptions and is not meant as individualized forecasting, with uncertainty that includes time to achieve full effects, the effect of eggs, white meat, and oils, individual variation in protective and risk factors, uncertainties for future development of medical treatments; and
changes in lifestyle.”

Dietary habits are estimated to contribute to 11 million deaths annually worldwide, and to 255 million disability-adjusted life-years (DALYs). One DALY, according to the World Health Organization “represents the loss of the equivalent of one year of full health”. In other words, there’s a lot of room for good in changing what we eat.

The team drew on existing databases to develop a computerized model to estimate how a range of dietary changes would impact life expectancy. The model is publicly available as the online Food4HealthyLife calculator, which you can use to get a better idea of how changing what you eat can benefit your lifespan. The team envisions that their calculator would also help physicians and policy-makers to understand the impact of dietary choices on their patients and the public.

For your typical young adult (20 years old) in the United States, the team reports that changing from the typical diet to an optimal one (as described by their model) could provide an increase in LE of roughly 10.7 years for women and 13 years for men. There is quite some uncertainty in these results — meaning that increases for women range between 5.9 years and 14.1, and for men between 6.9 and 17.3 — due to the effect of factors that the model doesn’t factor in, such as preexisting health conditions, socioeconomic class, and so on. Changing diets at age 60 would still yield an increase in LE of 8 years for women and 8.8 years for men.

“The differences in life expectancy estimates between men and women are mainly due to differences in background mortality (and particularly cardiovascular disease such as coronary heart disease, where men generally are at higher risk at an earlier age compared to women),” prof. Fadnes explained for ZME Science.

The largest gains in LE would be made by eating more legumes, more whole grains, more nuts, less red meat, and less processed meat.

So far, the research focused on the impact of diet on LE, but such changes could be beneficial in other ways, as well. Many of the suggestions the team makes are also more environmentally sustainable and less costly, financially. The team is now hard at work incorporating these factors into their online calculator, in order to help people get a better understanding of just how changes in diet can improve their lives, on all levels involved.

“We are working to include sustainability aspects in Food4HealthyLife too. Based on former studies, the optimal diets are likely to have substantial benefits compared to a typical Western diet also in terms of reduction in greenhouse gas emissions, land use, and other sustainability facets,” he added for ZME Science. We have not systematically investigated financial aspects yet, but several of the healthy options could also be cheap, such as legumes and whole grains.”

The paper “Estimating the Impact of Food Choices on Life Expectancy: A Modeling Study” has been published in the journal PLoS Medicine.