A new study shows a type of fasting diet similar to one popularised by Michael Mosley could help us live 12 percent longer.

We are all fully aware that what we eat plays a massive role in our health and wellbeing. Our diet can even impact how long we are expected to live, with those consuming a Mediterranean diet among those living longest.

But research has shown that how much we eat can also have an effect on our longevity.

The study, published in Nature journal, revealed that intermittent fasting could be the way to go. More specifically, a trial on mice showed that eating normally for five days while fasting for two consecutive days had significant life-extending benefits.

The diet followed in the trial is similar to the 5:2 diet championed by Dr Mosley, which suggests eating up to 800 calories on the two fasting days: the so-called Fast 800. Scientists also found life expectancy was increased by putting mice on calorie restricted diets.

As part of the study, 937 mice were split into five dietary groups. These included one with unrestricted access to food, two with calorie restrictions (60 percent and 80 percent of baseline calories), and two with intermittent fasting (one or two consecutive days per week without food).

The mice were then monitored throughout their lives, with regular health assessments and blood tests. It was found that both calorie restriction and intermittent fasting extended the lifespan of mice, with effects proportional to the degree of restriction.

Mice on 40 percent calorie restriction lived about nine months longer than those allowed to eat as much as they wanted. That’s equivalent to extending a human lifespan by more than a decade.

And mice that fasted for one or two days per week also experienced significant lifespan extensions, with those fasting for two days living longer than those fasting for one. That’s despite consuming nearly the same amount of food overall as their unrestricted counterparts.

One of the study leads Gary Churchill, from the Jackson Laboratory in Maine, explained: “Our study really points to the importance of resilience. The most robust animals keep their weight on even in the face of stress and caloric restriction, and they are the ones that live the longest. It also suggests that a more moderate level of calorie restriction might be the way to balance long-term health and lifespan.”

However, the study also demonstrated the potential downsides to extreme dietary restriction. Mice on the 40 percent calorie-restricted diet, while living the longest on average, also experienced significant loss of lean body mass and changes in their immune systems that could potentially make them more susceptible to infections.

“While caloric restriction is generally good for lifespan, our data show that losing weight on caloric restriction is actually bad for lifespan,” Professor Churchill added. “So when we look at human trials of longevity drugs and see that people are losing weight and have better metabolic profiles, it turns out that might not be a good marker of their future lifespan at all.”

On Michael Mosley’s Fast 800 website it says: “The new 5:2 is a highly effective approach to intermittent fasting, enabling weight loss and building a healthier brain and body. Some people start with the very fast 800 if they have a significant amount of weight to lose, or to kick start weight loss, while others start with the new 5:2 for gradual weight loss or to improve overall health.

"When following the new 5:2, schedule two days a week as 800-calorie ‘fasting days’, and follow a healthy Mediterranean-style diet for the rest of the week, with no calorie restriction, just sensible portions.”