Dietary Guidelines for Americans with Ultra-Processed foods (DGA-UP) study protocol: impact of dietary guidelines...

Ultra-processed food (UPF) consumption has generated a great deal of concern among nutrition scientists and consumers due to its potential relationship with increased risk of adverse health impacts. Evidence from intervention studies comparing UPF-rich and less-processed diets on cardiometabolic health outcomes is limited. Clinical trials that have been published to date focus on comparing more- and less-processed diets, as defined by the Nova system, and their impact on weight-related outcomes. Only one trial compares equally healthful more- and less-processed diets. The Dietary Guidelines for Americans with Ultra-Processed foods (DGA-UP) study will be the first trial to examine whether there is a differential effect to following recommendations from the 2020-2025 Dietary Guidelines for Americans (2020 DGA) including more- or less-processed foods as defined by the Nova classification system on cardiometabolic disease risk factors. A randomised controlled crossover dietary intervention study, DGA-UP will be conducted with 4-week provision of all meals to generally healthy male and female adults at eucaloric levels. The trial will consist of two dietary arms: (1) a less-processed 2020 DGA diet and (2) an ultra-processed 2020 DGA diet. The primary outcome is change in blood pressure on each diet from baseline to week 4. Both interventions will have excellent diet quality and contain similar amounts of macronutrients and micronutrients as well as the same types of food. DGA-UP will help to fill a significant research gap regarding potential impact of UPF on cardiometabolic health markers independent of food type, diet quality and micronutrient content.