People who eat healthy foods spend about $1.50 more on food each day—or $550 per year—than those who do not, according to a Harvard School of Public Health report published in BMJ Open.

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For their study, researchers reviewed 27 studies published between 2000 and 2011 that included food prices in 10 financially-sound countries, as well as healthy and unhealthy diet patterns. They calculated prices for a 200-calorie serving of healthy and unhealthy foods, and used diet patterns to estimate the cost of healthy and unhealthy 2,000-calorie-a-day diets.

They found that the healthiest diets—those rich in fruits, vegetables, fish, and nuts—cost significantly more than diets rich in processed foods, meats, and refined grains. The difference in price varied most for protein groups: Healthier protein options cost $0.29 to $0.47 more per 200-calorie serving than less healthy options.

Senior author Dariush Mozaffarian notes that $550 a year represents "a real burden for some families, and we need policies to help offset these costs."

According to the study, one reason unhealthy diets are less expensive is because food policies support the production of cheap, high volume commodities, and this has resulted in a complex system that produces and markets food in a way that "favor[s] sales of highly processed food products for maximal industry profit."

But, while healthy diets cost more in the short term, they may have larger long-term financial benefits because of reduced health costs, Mozaffarian says. He adds, "On the other hand, this price difference is very small in comparison to the economic costs of diet-related chronic diseases, which would be dramatically reduced by healthy diets" (Paddock, Medical News Today, 12/6; Wilson, "The Chart," CNN, 12/5; Goodman, HealthDay, 12/6).