The new U.S nutritional guidelines advise Americans to intake more potassium, dietary fiber, vitamin D and calcium. However, these dietary adjustments will likely add $380 per year to a person's yearly grocery bill. Currently, every American spends about $4,000 on food each year on average, according to the U.S. Department of Agriculture.

The researchers point out that the recommended healthy eating by the U.S. government can be so expensive that many Americans cannot afford to follow them.

Pablo Monsivais, acting assistant professor at the University of Washington and one of the study's authors, suggested that the government publish the most cut-price options along with their dietary recommendations. For instance, bananas and potatoes are the cheapest sources of potassium.

The study was based on a random telephone survey of roughly 2,000 adults living in King County, Washington, followed by a printed questionnaire that was returned by around 1,300 people. The survey participants marked what food they consumed, which the scientists analyzed for nutrient content and estimated cost. Study participants also filled out questionnaires detailing their eating habits.