Prescription medicines are now a major part of obesity care. This section explains how they work and how to eat and move while taking them. It does not give dosing advice, and it is not a substitute for a conversation with a licensed clinician.
What GLP-1 medicines are
GLP-1-based medicines mimic gut hormones that signal fullness and slow stomach emptying, which reduces appetite. FDA-approved options for chronic weight management include semaglutide (Wegovy) and tirzepatide (Zepbound), which also acts on a second hormone, GIP. The NIDDK explains that weight-management medicines are generally considered for adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition, alongside diet and activity.
Common side effects
Nausea, vomiting, diarrhea and constipation are among the common side effects listed for semaglutide by MedlinePlus, especially when starting or increasing a dose. Ongoing or severe stomach pain needs prompt medical attention.
A word on compounded and online products
Compounded versions are not FDA-approved, and the FDA has warned about unapproved GLP-1 products and dosing errors. Get any medicine through a licensed prescriber and a licensed pharmacy, and read the FDA’s consumer guidance.
Lifestyle still matters
A 2025 joint advisory from four obesity and nutrition societies stresses nutrient-dense eating, adequate protein, strength training and managing side effects as core parts of GLP-1 treatment.
Guides in this section
- What to Eat on a GLP-1 MedicationProtein-first meals, fiber, fluids and foods that can worsen nausea.
Sources
- NIDDK: Prescription Medications to Treat Overweight & Obesity
- MedlinePlus: Semaglutide Injection (NIH National Library of Medicine)
- FDA: Concerns with Unapproved GLP-1 Drugs Used for Weight Loss
- Nutritional Priorities to Support GLP-1 Therapy for Obesity: joint advisory from ACLM, ASN, OMA and The Obesity Society (May 2025)