Brain Outcomes With Lifestyle Change in Down Syndrome

Inclusion Criteria: * Diagnosis of Down syndrome * BMI of 25 to 50 kg/m2 * Ability to communicate through spoken language. * Ability to come to the University of Kansas Medical Center 3 times across 1 year for outcomes testing * Living at home with a parent/guardian, or in a supported living environment with a caregiver who assists with food shopping, meal planning, and meal preparation and agrees to serve as a study partner including providing transportation to our facilities for study assessments. Exclusion Criteria: * Diagnosis of dementia * Insulin dependent diabetes * Participation in a weight management program involving diet or physical activity in the past 6 mos. * Dairy allergy * Serious medical risk (e.g., cancer, recent heart attack, stroke, pregnancy, angioplasty) * Unwilling to be randomized * Contraindications for MRI, including metal implants or devices incompatible with MRI such as pacemakers, claustrophobia, and inability to lay in a supine position * Use of GLP-1 medications * Use of anti-amyloid medications