Removing steak, sausages and bacon from your diet at the age of 60 in favour of more fish, nuts and beans can add almost a decade onto your life, a study has found.

Myriad studies show that red and processed meats are bad for health, and they have been linked to an increased risk of cancer, heart disease and high blood pressure.

A new study from researchers at the University of Bergen, Norway, has discovered 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.

Switching from what the researchers called a “traditional Western diet” to a more nutritious menu at the age of 60 means that a man can expect to live to 90, opposed to 81 if he was to stick to his old habits. An average woman of 60 will reach 93, up from 85, the study claimed.

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 was to make the change after consuming sugary drinks and bacon butties while avoiding lentil soup for four decades.

In your 80s? You’ll add an extra three years

Older people can still benefit, the scientists found, as making the change at 80 still adds more than three years to a person’s 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 (1.8oz) of white meat – roughly one chicken thigh, 50g of refined grains and half an egg.

Vegetables, fruit, and legumes, however, should become stalwarts, consumed en masse.

In the paper, the researchers stated that the ideal diet features 400g (14oz) 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 which takes into account where a person lives, how old they are and their gender in order to gauge the impact of an improved diet.