Glucagon-like Peptide 1 (GLP-1) Receptor Agonist Therapy and Exercise Training in People With Obesity

The use of glucagon-like peptide receptor agonists (GLP-1 RAs) may have clinically important effects on skeletal muscle mass (SMM), and physical function. The effects of exercise training in conjunction with GLP-1 RA therapy on these outcomes has not been studied. Additionally, most people treated with GLP-1-based weight loss medications stop taking these medications within 1 year of initiating treatment. This is an important clinical concern because weight regain can occur after weight loss pharmacotherapy is stopped and the impact of stopping GLP-1 RA therapy on physical and metabolic function has not been studied. In this study, the investigators will conduct a 2-year randomized clinical trial to evaluate body composition, muscle, physical and metabolic function, muscle strength and appetite control and reward signaling in the brain in response to 1-year of GLP-1 RA therapy, with or without exercise training, and subsequent treatment cessation on muscle and appetite-related outcomes assessed 1-year after stopping treatment.

Inclusion Criteria: * i) obesity (Body Mass Index ≥ 30 kg/m2) * ii) decreased physical function (Modified Physical Performance Test score 17 to 31) * iii) approval of their primary physician to participate in this study. Exclusion Criteria: * i) unstable weight (\>4% change during the last 2 months before entering the study) * ii) ≥150 min per week of structured exercise (e.g., jogging, activities that cause heavy breathing and sweating) * iii) diabetes * iv) significant cardiopulmonary disease (heart failure, angina, uncontrolled hypertension, chronic obstructive pulmonary disease) or other organ dysfunction (e.g., renal insufficiency \[eGFR \1.5X the upper limit of normal (patients receiving treatment for hypothyroidism may be included provided their thyroid hormone replacement dose has been stable for at least 3 months) * ix) history of significantly active or unstable Major Depressive Disorder or other severe psychiatric disorder (e.g. schizophrenia, bipolar disorder, or other serious mood or anxiety disorder) within the last 2 months that would interfere with study participation * x) acute or chronic hepatitis, or other liver disease other than Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) * xi) family or personal history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 * xii) history of active or untreated malignancy or are in remission from a clinically significant malignancy (other than basal- or squamous cell skin cancer, in situ carcinomas of the cervix, or in situ prostate cancer) for less than 5 years * xiii) tobacco use, excessive alcohol intake (≥3 drinks/day for men and ≥2 drinks/day for women) or active substance abuse with illegal drugs by self-report, or regular marijuana use within 3 months of enrollment and unwilling to abstain from marijuana during the trial * xiv) Use of medications that are known to affect the study outcome measures or increase the risk of study procedures and that cannot be temporarily discontinued for this study * xv) have had bariatric surgery or plan to have endoscopic or bariatric surgery therapy for obesity * xvi) anemia (Hgb \