A new study from the Harvard School of Public Health (HSPH) demonstrates that the healthiest diets cost about $1.50 more per day than the least healthy diets. The findings, published in the British Medical Journal Open, are based on the most comprehensive examination to date comparing prices of healthy foods and diet patterns versus less healthy ones.
“People often say that healthier foods are more expensive, and that such costs strongly limit better diet habits,” said Mayuree Rao, a junior research fellow in the Department of Epidemiology at HSPH. “But, until now, the scientific evidence for this idea has not been systematically evaluated, nor have the actual differences in cost been characterized.”
The HSPH team conducted a meta-analysis of 27 existing studies from 10 high-income countries to answer this question. The studies included price data for included foods and for healthier versus less healthy diets. The team evaluated several factors, including 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 U.S. Department of Agriculture’s recommended average daily calorie intake for adults) for overall diet patterns. The team assessed both prices per serving and per calorie because prices can vary depending on the unit of comparison.
Healthier diet patterns — for example, diets rich in fish, nuts, fruits, and vegetables — were found to cost significantly more than unhealthy diets, such as those rich in processed foods, meats, and refined grains. A day’s worth of the most healthy diet patterns cost, on average, about $1.50 more per day than the least healthy ones.
The study findings suggest that unhealthy diets may cost less because food policies have focused on the production of “inexpensive, high volume” commodities. This 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.” The scientists say that given this reality, creating a similar infrastructure to support production of healthier foods might help increase availability — and reduce the prices — of more healthful diets.
“This research provides the most complete picture to-date on true cost differences of healthy diets,” said Dariush Mozaffarian, associate professor at HSPH and Harvard Medical School. “While healthier diets did cost more, the difference was smaller than many people might have expected. Over the course of a year, $1.50/day more for eating a healthy diet would increase food costs for one person by about $550 per year. This would represent a real burden for some families, and we need policies to help offset these costs. 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.”