Limiting Ultra-Processed Foods Alone Doesn't Ensure a Healthy Diet, Study Reveals

A new study, presented at NUTRITION 2024, the flagship annual meeting of the American Society for Nutrition, demonstrated that eating primarily minimally processed foods, as they are defined by the NOVA classification system, does not automatically make for a healthy diet, suggesting that the types of foods we eat may matter more than the level of processing used to make them.

Comparing 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 — the researchers found that the less processed menu reached its expiration date over three times faster without delivering any additional nutritional value.

In the study, researchers constructed two menus: a less-processed menu deriving 20% of its calories from ultra-processed foods and a more-processed menu deriving 67% of its calories from ultra-processed foods. The level of processing in each menu was determined using the NOVA system of classification.

Both menus were calculated to have a Healthy Eating Index score of about 43-44 out of 100, indicating poor adherence to the Dietary Guidelines for Americans. The researchers calculated that the median time to expiration for less-processed menu items was 35 days, versus 120 days for the more-processed menu items.

The study highlighted the disconnect between food processing and nutritional value. Notably, some nutrient-dense packaged foods can be classified as ultra-processed, such as unsweetened applesauce, ultrafiltered milk, liquid egg whites, and certain brands of raisins and canned tomatoes.

“This study indicates that it is possible to eat a low-quality diet even when choosing mostly minimally processed foods. The results indicated that building a nutritious diet involves more than a consideration of food processing as defined by NOVA. The concepts of ‘ultra-processed’ foods and ‘less-processed’ foods need to be better characterized by the nutrition research community,” said Julie Hess, PhD, a research nutritionist at the USDA-ARS Grand Forks Human Nutrition Research Center, who led the study.

Reference: Mark Messina, PhD, Soy Nutrition Institute Global, NUTRITION 2024, The flagship annual meeting of the American Society for Nutrition; AMERICAN SOCIETY FOR NUTRITION