Metabolomics-Driven Insights Into Ultra-Processed Foods

The goal of this dietary intervention study in generally healthy adults is to develop new ways to use blood samples to measure the common types of highly processed foods and beverages that people eat on a regular basis. The main aims to answer are: What small molecules are elevated in blood after eating different types of highly processed foods and beverages consistently for 1 week? Researchers will compare 3 different test diets with 1 control diet that does not have any highly processed foods in the same individuals to see which circulating blood markers change. Participants will: * Complete 3 diet phases, each 2 weeks long * Receive a meal plan and study foods and beverages to follow for each 2-week phase * Come to the clinic every week for blood draws, urine samples, and stool collection kits

Inclusion Criteria: * Adults, ages 20 to 65 years. * BMI 18.5 to 39.9 kg/m2. * No known food allergies, intolerances, or sensitivities (e.g., gluten, dairy, monosodium-glutamate). * Not following a restrictive diet for health, religious, or other reasons (e.g., vegetarian, vegan). * Willingness to participate and give informed consent. * Willingness to consume dietary intervention foods and beverages. Exclusion Criteria: * BMI \39.9 kg/m2. * Pregnant, lactating, or planning on becoming pregnant in the next 6 months. * History of bariatric surgery. * Currently taking medications impacting appetite or body weight. * History of major chronic diseases, including cardiovascular disease, type 1 or 2 diabetes, major gastrointestinal conditions, uncontrolled hypertension (seated blood pressure systolic \>140 mmHg or diastolic \>90 mmHg), history of invasive cancer, current use of immunosuppressants, and other major chronic diseases and conditions affecting participation, adherence, or study endpoints. * Unwilling or unable to comply with all in person scheduled visits, dietary protocols, study protocol, and other study procedures. * Food allergies or aversions to the foods provided in the dietary interventions. * Non-English speaking. * Other members of the same household are already participating in the research study. * Planning on moving out of the Boston area in the next 6 months.