A report from the U.S. Department of Agriculture finds that healthy food is no less expensive than junk food, putting to bed the long-standing assumption that healthy eating comes at a hefty cost.

Researchers examined national pricing data for more than 4,000 food items and ranked them based on price-per-calories, weight and portion size.  When measured by portion size and weight, the healthy foods were no more costly than unhealthy foods.  

They also found that when following the government's dietary guidelines, it's most expensive for people to meet the recommendations for protein and vegetables, followed by fruit.  The reason is that the government's recommendations in those categories for how much a person should consume each day is particularly high. 

Currently, the average American spends about 20 to 25 percent of their food budget on fruits and vegetables when, according to the USDA, they should spend closer to 40 percent.