Eating primarily minimally processed foods did not automatically make for a healthy diet, according to the results of a study presented at NUTRITION 2024, the annual meeting of the American Society for Nutrition.
Researchers compared two menus reflecting a typical Western diet — one emphasizing minimally processed foods and the other emphasizing ultra-processed foods, as categorized by the NOVA classification system. They found that the less processed menu was more than twice as expensive and reached its expiration date over three times faster without delivering any additional nutritional value.
"This study indicated that it was possible to eat a low-quality diet even when choosing mostly minimally processed foods. It also showed that more-processed and less-processed diets could be equally nutritious (or non-nutritious), but the more-processed diet had a longer shelf life and was less costly," state Julie Hess, Ph.D., a research nutritionist at the USDA-ARS Grand Forks Human Nutrition Research Center.
The researchers constructed a less-processed menu, which derived 20% of its calories from ultra-processed foods, and a more-processed menu, which derived 67% of its calories from ultra-processed foods. Both menus were calculated to have a Healthy Eating Index score of about 43-44 out of 100, reflecting poor adherence to the Dietary Guidelines for Americans.
The less-processed menu cost an estimated $34.87 per day per person compared with $13.53 per day for the more-processed menu. The median time to expiration of the less-processed menu items was 35 days versus 120 days for the more-processed menu items.
Dr. Hess noted that some nutrient-dense packaged foods were classified as ultra-processed, such as unsweetened applesauce, ultrafiltered milk, liquid egg whites, and some brands of raisins and canned tomatoes.
"Building a nutritious diet involved more than a consideration of food processing as defined by NOVA," Dr. Hess noted. "The concepts of 'ultra-processed' foods and 'less-processed' foods need to be better characterized by the nutrition research community."
The study was funded by a USDA Agricultural Research Service project grant.