Potatoes are a good source of nutrients and give the best value per penny, a new study has found.

One of the main reasons for the expanding waistline of the U.S is that it is really easy to buy cheap food that's packed with calories but low in nutrition. Another advantage of buying food that's high in sugar, fat and salt is that it can be stored for long, unlike fresh fruits and vegetables that can get all squishy within days of buying.

The study found that the often infamous potato can be a good provider of essential nutrients while still being easy on the pocket and staying good for long.

To put things in better perspective, greens occupy the top position in a healthy food chart, proving a large amount of vital nutrients. But, when it comes to affordability, starchy vegetables such as potatoes and beans win. For the study, researchers looked at the nutrients per unit cost of 98 vegetables including greens, orange/red vegetables, starchy legumes and other vegetables.

A medium sized potato has about 110 calories per serving and is a better source of potassium than a banana (620 g versus 450 g). Also it contains about half of a person's daily requirement of vitamin C and has no fat, sodium or cholesterol. The vegetable is a good low cost option for obtaining other nutrients such as magnesium and dietary fiber.

The study was conducted by Dr. Adam Drewnowski and colleagues from the University of Washington and was funded by the United States Potato Board.

"The ability to identify affordable, nutrient dense vegetables is important to families focused on stretching their food dollar as well as government policy makers looking to balance nutrition and economics for food programs such as the school lunch program and WIC. And, when it comes to affordable nutrition, it's hard to beat potatoes," said Adam Drewnowski, PhD and lead author of the study.

The study is published in the journal PLOS One.

A recent report had also shown that potatoes can feed millions of hungry people in Ethiopia- a region coping with global warming. Currently, the world produces about 300 million metric tons of potatoes per year and it is the third most consumed crop after rice and wheat.