Dr Michael Mosley is the diet and well-being mastermind behind the 5:2 and Fast 800 eating plans.

He has recently revealed how a particular veggie superfood can give people a boost and make them more active.

Beetroot works in the same way as Viagra and can act to lower blood pressure, according to the renowned health guru.

He told Masterchef winner Thomasina Miers on the 15.5 stories broadcast that in Roman times the vegetable was actually used as an aphrodisiac.

The TV presenter said it had many of the same characteristics as how the modern drug Viagra works by dilating veins.

Dr Mosley said that it was one of the vegetables he suggested people eat as often as possible but actually getting people to eat it was the main problem.

He suggested Thomasina should come up with some recipes to make it more appetising.

The former doctor explained that it was the chemicals - specifically nitrates - in beetroot which made it into a superfood.

In his book, Just One Thing, which has recently come out in paperback, the author has listed 30 lifestyle changes people can make which will make them healthier and lose weight and he talks about beetroot.

Dr Mosley said: "For those who are interested the biochemistry - the sciency bit - essentially beetroot is rich in nitrates., Nitrates are converted by bacteria in your mouth into nitric oxide. That causes vasodilation - expansion of your blood vessels.

"That's what brings your blood pressure down and what it also does, particularly with older people, it gives them a boost so they are able to become more active. The Romans used it as an aphrodisiac strangely enough.

"The mechanism is exactly the same as in Viagra. What Viagra does is lead to the release of nitric oxide and the expansion of blood vessels, but mainly around your genitalia. Another good reason to eat beetroot!"

Thomasina Miers replied: "It's so brilliant that's why the science is so good. When I read that I was fascinated by that. I told my children that when you eat this the idea that your blood vessels are dilating is just incredible."