The goal of this clinical trial is to learn about changes in body composition related to obesity medication use, and whether aerobic or resistance exercise training will impact these body composition changes. It will also provide information about whether aerobic or resistance exercise training has additional benefits on other health and fitness measurements. The main questions it aims to answer are:

• Is there a difference in the change in body composition (fat mass, lean mass, muscle mass, and bone content) between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in body weight and BMI between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in cardiorespiratory fitness between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in how much physical activity is completed between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in physical function between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in muscle strength between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in resting blood pressure between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in food intake between the standard medical care and the exercise conditions (aerobic training and resistance training)?
• Is there a difference in the change in health-related quality of life between the standard medical care and the exercise conditions (aerobic training and resistance training)?

Participants will:

• Participate in an intervention for a period of 6 months that involves being assigned to a no exercise/standard medical care condition, or a supervised exercise condition (aerobic training or resistance training).
• Visit the clinical before starting the study and at 6 months to complete study measurements of their body composition and other measurements to monitor their progress.
• Complete a brief monitoring session at weeks 6, 12, and 18 across the 6 months.
• Complete supervised exercise sessions at the research center 3x per week for 6 months (Participants in the exercise groups only: aerobic training or resistance training).

Inclusion Criteria:

• Both males and females of all race/ethnic groups are eligible for participation in this study.
• Age: Randomized Study: Adults that are 18 to <60 years of age. Observational Study: Adults that are >60 years of age.
• Newly prescribed AOM (semaglutide, tirzepatide) for the treatment of obesity, approval for treatment (pharmacy, insurance, etc.), and the participant agreeing to start this treatment and continue treatment for at least 6 months (the participant will be recruited prior to this medication being initiated).
• Body mass index (BMI) of >27.0 kg/m2 with at least one weight-related complication (hypertension, dyslipidemia, obstructive sleep apnea, or cardiovascular disease) provided it this does not compromise the ability to safely complete the screening or outcome measures or to engage in the prescribed exercise interventions), or >30 kg/m2 without weight-related complications. Enrollment will not be limited based on an upper BMI level provided that the participant meets the other eligibility requirements. However, weight or size limits of the dual-energy x-ray absorptiometry (DXA) system that is used to assess body composition must not be exceeded.
• Ability to provide informed consent prior to participation in this study.
• Clearance from the study physician for meeting all eligibility criteria for this study.

Exclusion Criteria:

• Type 2 diabetes.
• Report moderate-to-vigorous exercise for >60 min/week, and >1 day of structured cardiovascular or resistance exercise over the past 3 months.
• Report sustained weight loss of >3% in the past 3 months.
• History of metabolic/bariatric surgery.
• Females who are pregnant, pregnant within the past 6 months, or reporting a planned pregnancy during the study period.
• Report a current medical condition or treatment for a medical condition that could affect body weight or contradict engagement in any aspect of the outcome measures or interventions.
• History of muscle conditions that may impact the quality of muscle or response to the study interventions (e.g., myopathy, muscular dystrophy, rhabdomyolysis, etc.).
• Current congestive heart failure, angina, uncontrolled arrhythmia, symptoms indicative of an increased acute risk for a cardiovascular event, prior myocardial infarction or history of cardiomyopathy, coronary artery bypass grafting or angioplasty, conditions requiring chronic anticoagulation (i.e., recent or recurrent DVT).
• Resting systolic blood pressure of >160 mmHg or resting diastolic blood pressure of >100 mmHg. If medicated for blood pressure control, the medication dose needs to be stable for >6 months.
• Eating disorders that would contraindicate weight loss or physical activity.
• Alcohol or substance abuse.
• Current psychological condition that is untreated, hospitalization for a psychological condition within the past 12 months, or not being on a stable dose of treatment for at least 6 months.
• Report plans to relocate to a location not accessible to the study site or having employment, personal, or travel commitments that prohibit attendance at scheduled intervention sessions or assessments.

The summary data for each of the study outcomes and other additional demographic characteristics will be made available. The Study Protocol (which includes the statistical analysis plan), Manual of Procedures, Data Collection Forms, and a Data Dictionary to explain the data variables will be provided.

The data will be made available no later than the time of an associated publication of study outcomes or at the end of the performance period, whichever comes first. The data provided to the repository will be available indefinitely while that repository continues to exist.

The information included with the IPD will be made available to appropriate individuals only after the requester confirms their willingness to comply with an appropriate "Data Use Agreement" that complies with NIH policies, the policies of the institution where the study has been conducted, and the elements of informed consent.