NEW YORK – Researchers from Tufts and New York University published an article in the American Journal of Public Health looking at the “legal and administrative feasibility of a federal junk food tax to improve diet.” While some U.S. cities have jumped on the soda tax train—Berkley and Philadelphia for example—a national policy could take a bit more persuasion.

The researchers pointed to two solid examples: Hungary and Mexico. In 2011, Hungary put a four-cent tax on packaged food and drinks that contain high levels of sugar and salt in specific product categories, such as soft drinks, candy, snacks and fruit jams. Similarly, in 2013, Mexico passed an 8% tax on “non-essential” foods, including snacks, sweets, cereal-based products and nut butters, based on a specific caloric density threshold.

The American Journal of Public Health article concluded that Hungary’s model was the most ideal: considering the overall nutritional value of food, rather than number of calories. It even affected manufacturers: Nearly 40% of junk food manufacturers in Hungary altered recipes to make them healthier.

Don’t expect a junk food tax in the U.S. to happen anytime soon, but the health-food movement may take a more significant turn as retailers make healthier food more convenient and affordable.