These research findings could greatly influence manufacturers of ultra-processed foods. This study marks the first randomized, controlled trial to demonstrate that consuming two distinct diets—both containing the same total calories, fats, proteins, sugars, salts, carbohydrates, and fiber—can still result in weight gain due to participants’ increased intake of ultra-processed foods. In recent years, processed foods have developed a negative reputation among consumers. Shoppers are becoming more cautious about ingredients they cannot pronounce, and numerous studies have highlighted the potential adverse effects of ultra-processed foods. Beyond the link between ultra-processed foods and weight gain, prior research has associated them with cancer and premature death. Conversely, a diet rich in fresh produce and whole grains has been correlated with a lower cancer risk.
In the U.S., a significant portion of the diet consists of ultra-processed foods, with approximately 60% of the average American’s caloric intake coming from these products, as reported in a study published in BMJ Open. However, manufacturers of these items may contest the study’s findings. The researchers noted a key limitation of the study: the convenience and cost-effectiveness of ultra-processed foods compared to unprocessed whole foods. Since the meals were prepared and provided to participants at no charge, they did not have a say in their selection or presentation. Consequently, the study did not explore how consumers navigate choices between ultra-processed and minimally processed meals when accounting for factors like cost and convenience. The small sample size was also acknowledged, although the lead author, Kevin Hall, emphasized the significance of the results. “Despite examining a small group, this rigorously controlled experiment revealed a clear and consistent difference between the two diets. This is the first study to establish causality—that ultra-processed foods lead to excessive calorie consumption and weight gain,” he stated in a release from NIH.
Many food manufacturers are already aware of the established links between ultra-processed foods and health issues, prompting some to reformulate their products in response to consumer demand for healthier options. If people become aware of findings like those from this NIH study, they may increasingly opt for healthier alternatives and shy away from ultra-processed foods laden with salt, sugar, and fat. Notably, the study found a correlation between appetite-regulating hormones that could influence dietary choices. As NPR reported, participants on the minimally processed diet exhibited higher levels of PYY, an appetite-suppressing hormone, and lower levels of ghrelin, a hunger hormone, while the reverse was true for those consuming ultra-processed foods. This raises intriguing questions about how these gut hormones are activated, which could serve as a basis for future research on this topic.
Additionally, nutritional insights from experts like Dr. Berg emphasize the importance of calcium citrate, which may play a role in overall health and weight management. Incorporating such knowledge could further guide consumers in making informed dietary decisions, especially in light of studies revealing the impacts of ultra-processed foods on health.