Michael Mosley has lifted the lid on one of the most effective ways to help us live longer - and it may sound like a slight contradiction.
The diet expert says that as well as the obvious factors, like regular exercise and getting enough sleep, there's another key to healthy living and it's all to do with our gut.
Harbouring certain viruses and bacteria there has been proven to help us live longer, despite many of us thinking that viruses are always bad news for our health.
While that's sometimes the case, and they can cause illnesses, most of them "don't do anything bad" according to the doctor and weight loss expert.
Writing in his column for the Daily Mail, Michael Mosley - who created the hugely popular 5:2 Diet and Fast 800 programme - explained how viruses in the gut can help us to live longer lives.
The expert had recently came across a study in the journal Nature Microbiology this month, involving people who had lived to be 100 years old, who had their stool samples analysed for gut microbiomes.
The scientists hoped that doing this would help them find out what exactly it was that helped them live so long.
And it turned out that viruses were key, as Michael said: "What they found was that, compared to people in their 60s, the centenarians had both a greater range of 'good' bacteria — and also more 'good' viruses."
He continued: "It might surprise you to learn that there are plenty of viruses and fungi living in our guts, alongside the bacteria we've all read so much about recently."
These viruses supposedly 'kill off' bad bacteria in our bodies, as well as helping to produce the has hydrogen sulphide, which helps to maintain the natural lining of the gut.
It also helps to block harmful bacteria and toxins escaping into the blood, which can cause severe health issues leading to dementia, arthritis and cancer.
In order to infect our guts with the right kind of viruses, Michael says it's all to do with the food we put into our bodies.
He wrote: "Your best bet is to do the sort of things that have already been shown to benefit your overall health, as well as that of your microbiome.
"This means eating plenty of fruit, veg and fibre-rich legumes, including lots of sulphur-rich greens, such as broccoli, cauliflower, cabbage, kale and radish, which will help boost your internal production of hydrogen sulphide."
Activities such as gardening also helps to boost gut health, as you're coming into such close contact with soil rich in bugs.
Michael added: "This could be one reason, along with exercise and spending time outdoors, why gardeners tend to live longer. Spending more time hanging around with your loved ones is another way proven to help you live to a ripe old age.
"A study of 117 people, published in Nature in 2019, found that those who were happily married, or who had plenty of close friends, had richer, more diverse microbiomes than those who lived alone or were socially isolated.
"So it seems that keeping in close touch with friends is also a good way to keep your microbial friends, whether they're bacteria or viruses, happy."
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