The goal of this study is to identify people at risk of weight regain after stopping an injectable weight loss drug. The main question the investigators aim to answer is: Can weight regain be predicted by measuring circulating Agouti-related peptide, a small protein coming from the brain?

This study will enroll people who are taking an injectable weight loss drug, have lost weight with the help of this drug, and are required by their health insurance plan to discontinue treatment. Participants will first be screened for health conditions that would prevent them from entering the study. Once enrolled, participants will be asked to have the following testing while still on the injectable weight loss drug: body weight measurement, body composition (fat and lean mass), resting energy expenditure (calories burned), multiple blood draws after overnight fast and after drinking and nutritional shake urine collection, urine collection, measurement of heart rate, measurement of physical activity and sleep, questionnaires. Participants will then stop taking the injectable weight loss drug when the prescription runs out, and the same tests will be repeated 3 months later.

Inclusion Criteria:

• adults 18 years or older
• men and women
• prescribed an incretin-mimetic for weight loss and for whom insurance coverage for this specific drug will lapse
• any ethnicity

Exclusion Criteria:

• weight > or = 400 lb
• type 1 or type 2 diabetes
• patients taking steroid medications
• anemia
• heart disease
• advanced kidney disease (CKD stage 4 and 5)
• decompensated liver disease
• hyperthyroidism
• untreated hypothyroidism
• active cancer
• post solid organ or bone marrow transplant
• HIV/AIDS
• pregnancy/plan for pregnancy in the next 6 months
• breastfeeding
• post-menopausal women
• current smoker
• current recreational drug use
• night shift or rotating shift workers

All datasets that pass quality control procedures and any other data that are deemed necessary to validate and replicate research findings will be shared.

The data deposited will be made available to all investigators in the research community as soon as possible but no later than 12 months from the completion of the funding period or upon acceptance of the data for publication and release from journals, whichever is earlier. Requests for data will be filled in a timely manner, usually within 2 to 6 weeks of the request, depending on the chronological position of the request within the queue. In addition, research data which documents, supports, or validates the published research findings, will be made available (electronically or mailed hard-copies) upon request to NIH-funded research programs. The duration of preservation and sharing of the data will be a minimum of 10 years after the funding period.

Other researchers will be able to access the IPD if they submit a proposal that describes planned analyses. A data sharing agreement must be signed. Researchers interested in the IPD can contact Dr. Morselli by email and send documents by email. Dr. Morselli will then share the ICR.