Healthier foods and diet patterns cost more than less healthy options, according to a new study the Huffington Post reported.

Researchers from the Harvard School of Public Health found the healthiest diets cost about $1.50 more per day - or about $550 per year - than the least healthy diets, confirming a speculation that, until now, had not been systematically evaluated, according to a press release.

"People often say that healthier foods are more expensive, and that such costs strongly limit better diet habits," lead author Mayuree Rao, a junior research fellow in the Department of Epidemiology at HSPH, said in a statement. "For many low-income families, this additional cost represents a genuine barrier to healthier eating. Yet, this daily price difference is trivial in comparison with the lifetime personal and societal financial burdens of diet-related chronic diseases."

Their findings are based on the most comprehensive examination to date comparing prices of healthy foods and diet patterns vs. less healthy ones. They conducted a meta-analysis of 27 existing studies from 10 high-income countries.

The differences in prices per serving and per 200 calories for particular types of foods, and prices per day and per 2,000 calories (the United States Department of Agriculture's recommended average daily calorie intake for adults) for overall diet patterns were examined. And they assessed prices per serving and per calorie because prices can vary depending on the unit of comparison, according to a press release from the university.

Based on their research, among the different food groups, meats and proteins had the largest price differences, with healthier options costing about $0.29 more per serving and about $0.47 more per 200 calories than less healthy options. Price differences for other food groups, such as grains, dairy, snacks and sweets, and fats and oils, were much smaller, ranging from $0.02 to $0.12.

They said they believe unhealthy diets may cost less because food policies have focused on the production of "inexpensive, high volume" commodities, which has led to "a complex network of farming, storage, transportation, processing, manufacturing, and marketing capabilities that favor sales of highly processed food products for maximal industry profit."

Researchers said a similar infrastructure to support production of healthier foods might help increase availability-and reduce the prices-of more healthful diets.