A sustained dietary change may give substantial health gains for people of all ages, adding up to 9 years to lifespan, a Norwegian modelling study in PLOS Medicine. The research team has an online tool called the Food4HealthyLife calculator, where a person can input their diet and see how it alters their life expectancy.
Swopping a “traditional Western diet” for a more nutritious menu from age 60 means a man can expect to live to 90, as opposed to 81. And the average woman of 60 will reach 93, up from 85.
The research team has also created an online tool called the Food4HealthyLife calculator, where a person can input their diet and see how it alters their life expectancy.
Myriad studies have showed red and processed meats are bad for health, and have been linked to an increased risk of cancer, heart disease and high blood pressure.
This latest study, from researchers at the University of Bergen, Norway has found that following an “optimal diet” from the age of 60 adds 9.1 years to the life expectancy of a 60-year-old European man, and 8.1 years for a woman.
The overall increase in expected lifespan is greater if a person adopts the overhauled feeding regimen at an earlier age, but not by much. For example, if a 20-year-old woman subscribed to the perfect diet, she would add 10.4 years to her life expectancy – just 2.3 years more than if she were to make the change after consuming sugary drinks and bacon butties while avoiding lentil soup for four decades.
Older people can still benefit, the scientists found, as making the change at 80 still adds more than three years to a personʼs life expectancy. While the optimal diet has clear benefits for longer life, it comes at a hefty cost. Red and processed meat are banned, for example, as are drinks sweetened with sugar.
On any given day, the diet states that a person should eat no more than 50g of white meat – roughly one chicken thigh, 50g of refined grains and half an egg. Vegetables, fruit, and legumes, however, should become staples, consumed en masse.
In the paper, the researchers stated that the ideal diet features 400g of both fruits and vegetables, akin to 10 portions, twice the five-a-day touted by health experts. As an example, this would mean eating one big tomato, one sweet pepper, mixed salad leaves, half an avocado, a small bowl of vegetable soup, one banana, one orange, one apple, one kiwi and a handful of berries every single day.
The researchers created a computer model that takes into account where a person lives, how old they are and their gender, to gauge the impact of an improved diet.
This provided the backbone for the peer-reviewed study, and subsequently turned into an online tool called the Food4HealthyLife calculator, where a person can input their diet and see how it alters their life expectancy.
“The Food4HealthyLife calculator could be a useful tool for clinicians, policymakers, and lay-people to understand the health impact of dietary choices.”
The model and calculator breaks down where the biggest gains to life expectancy come from, and eating more legumes was the single best thing a person could do.
Going from none a day, as is typical in the Western diet, to 200g, the same as one big cup of soaked beans, lentils or peas, adds 1.6 years to a 60-year-oldʼs life expectancy.
Eating 200g of fish a day, roughly one large slice of herring, adds 0.4 years on its own, while skipping red and processed meat adds 1.2 years each.
Dr Lars Fadnes, the paper’s lead author, added: “Until now, research has shown health benefits associated with separate food groups or specific diet patterns, but given limited information on the health impact of other diet changes. Our modelling methodology has bridged this gap.”
Study details
Estimating impact of food choices on life expectancy: A modelling study
Lars T. Fadnes, Jan-Magnus Økland, Øystein A. Haaland, Kjell Arne Johansson.
Published in PLOS Medicine on 8 February 2022
Abstract
Background
Interpreting and utilising the findings of nutritional research can be challenging to clinicians, policy makers, and even researchers. To make better decisions about diet, innovative methods that integrate best evidence are needed. We have developed a decision support model that predicts how dietary choices affect life expectancy (LE).
Methods and findings
Based on meta-analyses and data from the Global Burden of Disease study (2019), we used life table methodology to estimate how LE changes with sustained changes in the intake of fruits, vegetables, whole grains, refined grains, nuts, legumes, fish, eggs, milk/dairy, red meat, processed meat, and sugar-sweetened beverages. We present estimates (with 95% uncertainty intervals [95% UIs]) for an optimised diet and a feasibility approach diet. An optimal diet had substantially higher intake than a typical diet of whole grains, legumes, fish, fruits, vegetables, and included a handful of nuts, while reducing red and processed meats, sugar-sweetened beverages, and refined grains. A feasibility approach diet was a midpoint between an optimal and a typical Western diet. A sustained change from a typical Western diet to the optimal diet from age 20 years would increase LE by more than a decade for women from the United States (10.7 [95% UI 8.4 to 12.3] years) and men (13.0 [95% UI 9.4 to 14.3] years). The largest gains would be made by eating more legumes (females: 2.2 [95% UI 1.1 to 3.4]; males: 2.5 [95% UI 1.1 to 3.9]), whole grains (females: 2.0 [95% UI 1.3 to 2.7]; males: 2.3 [95% UI 1.6 to 3.0]), and nuts (females: 1.7 [95% UI 1.5 to 2.0]; males: 2.0 [95% UI 1.7 to 2.3]), and less red meat (females: 1.6 [95% UI 1.5 to 1.8]; males: 1.9 [95% UI 1.7 to 2.1]) and processed meat (females: 1.6 [95% UI 1.5 to 1.8]; males: 1.9 [95% UI 1.7 to 2.1]). Changing from a typical diet to the optimized diet at age 60 years would increase LE by 8.0 (95% UI 6.2 to 9.3) years for women and 8.8 (95% UI 6.8 to 10.0) years for men, and 80-year-olds would gain 3.4 years (95% UI females: 2.6 to 3.8/males: 2.7 to 3.9). Change from typical to feasibility approach diet would increase LE by 6.2 (95% UI 3.5 to 8.1) years for 20-year-old women from the United States and 7.3 (95% UI 4.7 to 9.5) years for men. Using NutriGrade, the overall quality of evidence was assessed as moderate. The methodology provides population estimates under given assumptions and is not meant as individualised forecasting, with study limitations that include uncertainty for 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.
Conclusions
A sustained dietary change may give substantial health gains for people of all ages both for optimised and feasible changes. Gains are predicted to be larger the earlier the dietary changes are initiated in life. The Food4HealthyLife calculator that we provide online could be useful for clinicians, policy makers, and laypeople to understand the health impact of dietary choices.
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