Switching to a healthier diet in middle age could add more than eight years to your life.
Moving from a typically British unhealthy diet to following the NHS Eatwell Guide, for a 40-year-old woman, could help her live approximately eight years and seven months longer.
That could mean living to the age of 86 instead of 77.
For a 40-year-old man, the same dietary shift could help extend his life expectancy by almost nine years, from dying aged 74 to almost making it to the age of 83.
The most important dietary changes to live longer, according to a study of more than 460,000 people in the UK, are cutting down on sugary drinks and processed meats like sausages and bacon, while consuming more nuts and whole grains, like those found in whole-grain bread and healthy breakfast cereals.
The good news is that the study results suggest is it is never too late to overhaul your diet.
Even 70-year-olds shifting from an unhealthy diet to strictly following the Eatwell Guide saw almost half the increase in life expectancy seen in 40-year-olds.
A 70-year-old man could live for four years longer, to the age of 86, with a 70-year-old woman living for about an extra four years and five months, to beyond her 88th birthday.
The Eatwell Guide advises people eat five portions of fruit and vegetables a day, while consuming enough starchy and protein-rich foods, and reducing intake of foods high in fat, salt and sugar.
Professor Lars Thadnes, who led the study from the University of Bergen, said: ‘Healthy eating can prevent premature deaths from things like heart attacks and strokes.
Eat at least 5 portions of a variety of fruit and vegetables every day. All fresh, frozen, dried and canned fruit and vegetables count;
Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain;
30 grams of fiber a day: This is the same as eating all of the following: 5 portions of fruit and vegetables, 2 whole-wheat cereal biscuits, 2 thick slices of wholemeal bread and large baked potato with the skin on;
Have some dairy or dairy alternatives (such as soya drinks) choosing lower fat and lower sugar options;
Eat some beans, pulses, fish, eggs, meat and other proteins (including 2 portions of fish every week, one of which should be oily);
Choose unsaturated oils and spreads and consuming in small amounts;
Drink 6-8 cups/glasses of water a day;
Adults should have less than 6g of salt and 20g of saturated fat for women or 30g for men a day.
‘People changing their diet as much as possible could help to achieve targets to reduce these avoidable deaths.
‘A key priority is for people to reduce their consumption of sugary drinks like cola and lemonade, and processed meats like bacon and sausages, and to eat more whole grains and nuts.
‘The Eatwell Guide provides a framework to be more aware of what we are consuming.’
The research, published in the journal Nature Food, looked at 467,354 people involved in the UK Biobank study, who filled out questionnaires on what they had eaten in the previous year.
These people were tracked over time, to see the age at which they died, which revealed the types of diet linked to a longer life.
Those with an unhealthy diet, who were in the fifth of people most likely to die prematurely, typically ate only a small amount of vegetables, fruit, whole grains, nuts, legumes, fish, white meat and milk or dairy products – or none at all.
But they consumed a substantial amount of processed meat, sugary drinks, eggs and refined grains – processed, rather than whole grains, such as those found in white bread, white rice and biscuits.
The largest gains from following the Eatwell Guide were seen in people with this type of unhealthy diet.
But even those with an average diet could add more than a year to their life by switching to following the Eatwell Guide recommendations at the age of 40.
The biggest gains in life expectancy were found for those who ate the healthiest diet seen among the study participants.
These people had a high intake of vegetables, nuts, legumes like lentils and chickpeas, and milk and dairy, while eating low amounts of processed meat and refined grains, and not too much red meat, eggs or sugary drinks.
If people with the most unhealthy diet moved to the most healthy diet, the results suggest, they could add more than a decade to their life expectancy at the age of 40, and more than five years by making the change at the age of 70.
However following the Eatwell Guide achieved about 80 per cent of the benefit seen for the most healthy diet, and the guide’s simple rules may be more straightforward for people to follow in real life.
The study found the benefits from eating healthily linked with life expectancy, even after taking into account other factors like whether people smoked, the amount of alcohol they drank, their age and level of exercise.
The average Briton has half a litre of sugary drinks a day, 50 grams of processed meat, which is the equivalent of six slices of bacon, and 100 grams of red meat, previous evidence has shown.
Unhealthy diets are estimated to cause more than 75,000 premature deaths a year in the UK.