Soda, cheese puffs, and candy might spring to mind when you think of processed foods. It might surprise you, however, that milk, dried fruit and frozen vegetables are processed foods, too.
[Photo: When studying the grocery-purchasing habits of more than 157,000 U.S. households, UNC researchers found that more than 60 percent of households purchased highly processed foods and beverages containing high levels of saturated fat, sugar, and sodium. More than 83 percent of households derived the majority of caloric energy from high-convenience, ready-to-eat or ready-to-heat foods. Photos from Flickr/Creative Commons by frankleleon, Kendra and sameold2010]
The United States government defines food processing as any procedure that alters food from its natural state. This includes pasteurizing, drying, freezing, and canning, as well as adding ingredients – most commonly, sugar, salt and/or fat.
To better examine the relationship between food’s degree of processing, convenience of preparation, and nutritional quality, Dr. Jennifer Poti, research assistant professor of nutrition at the UNC-Chapel Hill Gillings School of Global Public Health, developed classification systems to subdivide food products into categories based upon the complexity and purpose of processing. These four categories range from “unprocessed/minimally processed” to “highly processed.”
Foods and beverages also were classified based upon convenience, to distinguish items that are ready-to-eat or ready-to-heat from ones that require cooking or other preparation.
The research, co-authored by Dr. Michelle Mendez, assistant professor, Dr. Shu Wen Ng, research assistant professor, and Dr. Barry Popkin, W. R. Kenan Jr. Distinguished Professor, all in the department of nutrition at the Gillings School, was published in the June 1 issue of the American Journal of Clinical Nutrition.
The research team used the 2000-2012 Homescan Panel to analyze purchases of prepackaged food and beverages by more than 157,000 U.S. households. Using the categories developed, they classified the products by degree of industrial processing and convenience of food preparation.
After classifying more than 1.2 million products through the use of barcode-specific descriptions and ingredient lists, the researchers compared median saturated fat, sugar, and sodium content across levels of processing and convenience.
They found a stable trend between 2000 and 2012, in which more than three-fourths of calories in prepackaged purchases came from moderately (15.9 percent) and highly (61.0 percent) processed foods and beverages.