The goal of this study is to examine how tirzepatide affects body composition, bone health, and physical performance in older adults over a nine-month period. Participants will take tirzepatide weekly, have clinic visits every 4 weeks, meet study doctor and registered dietitian every 4 weeks in person or video conference, attend group intervention sessions twice a month via video conference, weigh daily with a study-provided smart scale, keep a record of all foods and beverages consumed, and use a study-provided activity tracker to keep track of daily step counts.