Potatoes have been seen by dieters as a carb-heavy devil vegetable, but researchers are now saying they might be the latest superfood.

Eating a portion twice a day, according to the researchers in the US, can reduce blood pressure without making you put weight on.

Sadly, chips and roasties are out – microwaved potatoes without butter, oil or ketchup are ideal, and baked, boiled and mashed spuds are also good.

A study was carried out, where 18 people who were overweight and on medication to lower blood pressure ate six to eight golf ball-sized potatoes with their lunch and dinner.

After a month, their blood pressure had reduced more than it had on the tablets – and none of the subjects put on any weight.

The potatoes used in the study were purple, but researchers believe normal potatoes should have the same benefits when cooked with their skins on, which is where the health-boosting chemicals – similar to blood pressure drugs –are found.

Researcher Joe Vinson from Scranton University, Pennsylvania, said: "The potato, more than perhaps any other vegetable, has an undeserved bad reputation that has led many health-conscious people to ban them from their diet."

He added: "Mention 'potato' and people think 'fattening, high-carbs, empty calories.' In reality, when prepared without frying and served without butter, margarine or sour cream, one potato has only 110 calories and dozens of healthful phytochemicals and vitamins.

“We hope our research helps to remake the potato's popular nutritional image."

He also said that lowering blood pressure cuts the risk of heart attacks and strokes.