A new study has revealed that consuming a diet rich in less-processed foods does not necessarily translate to better health.
The research, led by Dr. Julie M. Hess from the USDA-ARS Grand Forks Human Nutrition Research Center, shows that diets focused on minimally processed foods can be just as nutrient-poor as those loaded with ultra-processed foods, and at a much higher cost.
Key Findings
American scientists compared two Western-style diets: one dominated by minimally processed foods and the other by ultra-processed foods. Despite popular belief, the less-processed diet did not provide any additional nutritional value over the ultra-processed one.
- Cost: The minimally processed diet was found to be more than twice as expensive, costing $34.87 per person per day compared to $13.53 for the ultra-processed diet. This highlights the financial burden of eating “clean.”
- Shelf Life: Foods in the less-processed diet had a median shelf life of 35 days, significantly shorter than the 120 days for the ultra-processed diet. This suggests practical challenges in maintaining a less-processed diet, especially for those with limited access to fresh foods.
- Nutritional Quality: Both diets had similar Healthy Eating Index (HEI) scores—44 for the less-processed and 43 for the ultra-processed—reflecting poor adherence to the Dietary Guidelines for Americans.
The Reality of “Clean Eating”
The study highlights the complexities of food processing and its impact on diet quality. Ultra-processed foods, which include items like sugary drinks, refined grains, and processed meats, are often criticized for their high levels of added sugars, fats, and salts. However, the research found that a diet primarily consisting of less-processed foods still fell short in providing a high-quality diet.
Dr. Hess explained, “This study indicates that it is possible to eat a low-quality diet even when choosing mostly minimally processed foods. More-processed and less-processed diets can be equally nutritious—or non-nutritious—but the more-processed diet may have a longer shelf life and be less costly.”
Broader Implications
The study builds on previous research by Dr. Hess and her team, which demonstrated that it is possible to construct a high-quality diet with a significant proportion of calories from ultra-processed foods. This new research flips the question, asking whether a low-quality diet can be created from mostly simple, less-processed foods. The answer, it turns out, is yes.
The findings underscore the need for a nuanced understanding of food processing and diet quality. While ultra-processed foods are often demonized, some nutrient-dense packaged foods, such as unsweetened applesauce and ultra-filtered milk, also fall into this category.
“The results of this study indicate that building a nutritious diet involves more than a consideration of food processing,” Dr. Hess noted. “The concepts of ‘ultra-processed’ and ‘less-processed’ foods need to be better characterized by the nutrition research community.”
Conclusion
This research highlights the “disconnects” between food processing levels and nutritional value, challenging the notion that simply cutting out ultra-processed foods will lead to a healthier diet. The findings were presented at the annual meeting of the American Society for Nutrition in Chicago, offering new insights into the complexities of dietary guidelines and food choices.
Reference:
Hess, J. M., Comeau, M. E., Scheett, A. J., Bodensteiner, A., Levine, A. S., Messina, M., & Palmer, D. (2024). Unprocessed, but SAD: A Standard American Diet Made With Less-Processed Foods Is Still a Standard American Diet. Paper presented at the Nutrition 2024 conference. USDA-ARS Grand Forks Human Nutrition Research Center.
