Ultra-processed foods (UPFs) are important components of U.S. diets, accounting for ~60% energy intake by Americans. UPFs, by definition, are products of industrial formulations. Typical UPFs are processed meats, sugar-sweetened beverages (SSBs), fast foods, etc. As such, it is not surprising that the consumption of total UPFs is consistently associated with risk of coronary heart disease (CHD) and other cardiometabolic conditions in cohort studies. In a seminal, domiciled feeding trial conducted by Dr. Kevin Hall (Consultant),consumption of a UPF-centric diet led to significant, increased energy intake and weight gain after two weeks among 20 healthy individuals. Meanwhile, in our cohort studies, we found clear heterogeneity among food groups within the broad UPF category for their associations with cardiometabolic conditions. The positive associations between UPF intake and diabetes were largely driven by refined breads, SSBs, processed meats, and ready-to-eat mixed dishes, whereas other UPFs, including cereals, whole grain breads, savory snacks, and yogurt were associated with lower risk. Our analysis of CHD risk reveals a similar pattern. These data strongly suggest that consumption of individual UPF groups may yield differential health effects, but this hypothesis has not been examined systematically. To dissect the roles of diet quality and UPFs in human health, building upon our previous work, in this competing renewal we propose to conduct a series of inter-connected projects that consist of randomized feeding trials, biomarker discovery and validation, and prospective epidemiological investigations. Since healthy plant-based diets that emphasize fruits and vegetables, whole grains, etc. and de-emphasize SSBs, refined grains, and animal products are typically associated with lower CHD risk and other outcomes, we will compare healthy plant-based diets that emphasize UPFs or unprocessed, or minimally processed foods, respectively, to assess the health effect of food processing.
