Ultra-processed Food Consumption and Health Pilot Study

The investigators will conduct an out-patient cross-over trial comparing the Nutrition for Precision Health (NPH) purple diet and a diet high in ultra-processed foods (UPF diet) with participants randomized equally to one of two conditions. Assessments of study outcomes will be conducted at baseline prior to randomization, and pre- and post- each dietary condition. The overarching aim is to determine the feasibility of the study approach, and to explore the effects of the dietary conditions on a number of clinical and metabolic outcomes. Participants in this study will be 6 adults (both males and females) recruited from the community. Participants will receive each dietary condition for 14 days, with at least a 14-day wash-out period between conditions. The order of the conditions will be randomized. Participants in both intervention conditions will be provided with meals and snacks prepared by the Pennington Biomedical Metabolic Kitchen. The total daily kilocalories, energy density, and macronutrient content of the two diets presented to the participants will be equivalent across the two conditions. Participants will be asked to consume only the foods provided according to a daily menu (including up to 2 cups of coffee or tea), water, and up to 12 oz. of artificially-sweetened beverages, and to adhere to their other usual routines (e.g., exercise, sleep, medication use) throughout the study. Both diets will be isocaloric and will be provided using 3-day cycle menus, prepared by the Metabolic Kitchen. Menus will provide 3 meals and at least one snack. Participants will have some flexibility to distribute their meals and snacks across each day according to their preference. For menu planning, a 2100 kcal/d diet with scaled adjustments for individual energy needs will be planned. Templates will be developed that consist of 1600kcal, 2100kcal, 2600kcal, 3200kcal, and 3700kcal menus; 100 or 200 kcal foods that conform to the diet pattern and macronutrient profile will be added to the menu template (1600, 2100, 2600, 3200, or 3700 kcal) to deliver energy to the nearest hundred-kcal of estimated energy needs. These foods will also be added or removed from menus in cases of sustained weight loss or weight gain. Participants will pick up study meals two to three times per week and will be provided with a 2 to 4-day meal supply at each pick-up. Meals will be assembled in advance of participant pick up and according to dietary intervention assignment, energy requirements and the allowed substitutions for food preferences. At the time of food dispensing, the participant's identity will be verified to match the provided meals. Meals will be packaged in a cooler for temperature-controlled transport along with instructions for retherming as needed. The study outcomes will be collected immediately prior to and after each dietary condition.