The definition of obesity is not excess weight. Obesity is a chronic medical condition caused by an excessive and unhealthy accumulation of body fat. Therefore, the number on the scale is only part of the story. When you lose weight, it can be due to a loss of fat, muscle, or water.

Patients on GLP-1 medications have seen concerns about muscle loss on social media, and they are worried about it. The concern is reasonable, and the good news is that most of it is preventable with the right habits and the right follow-up.

Dr. Michael Baptista is a bariatric surgeon in Jacksonville who prescribes and monitors GLP-1 medications through a six-month, physician-supervised medical weight loss program. Protecting muscle is one of the things that program is built around.

Why weight loss can include muscle

Any significant weight loss, whether from diet, surgery, or medication, takes some lean tissue along with fat. GLP-1 medications reduce appetite, and when people eat much less, protein intake often falls with everything else. The body draws on muscle when protein is short and when muscles are not being asked to work. In clinical studies of these medications, lean tissue has accounted for a meaningful share of the weight lost, similar to what is seen with other forms of rapid weight loss.

In other words, the medication is not attacking muscle. Eating less without protecting muscle is what costs it.

Why it matters

Strength and everyday function: climbing stairs, carrying groceries, getting up from a chair.
Metabolism: muscle burns more energy at rest than fat does, so keeping it helps keep the results.
Balance and falls, especially for patients over 60, when muscle is harder to rebuild.
Long-term results: patients who keep their strength tend to stay active, and staying active is one of the strongest predictors of keeping weight off.

How to protect your muscle

These are the habits Dr. Baptista's team reviews with patients in the program. The specific targets are set with the dietitian for each patient.

Protein first. Eat protein at every meal, and eat it first, before appetite runs out. Lean meats, fish, eggs, Greek yogurt, cottage cheese, beans, and protein shakes all count.
Resistance training. Two or three sessions a week of strength work: weights, resistance bands, or body-weight exercises such as squats, wall push-ups, and step-ups. Walking is good for the heart; it is not enough on its own to protect muscle.
Steady, not extreme. Losing weight faster than planned is not a win if strength goes with it. Follow-up visits exist partly to keep the pace right.
Water. Dehydration makes fatigue and weakness worse, and reduced appetite often means reduced drinking too.
Sleep. Muscle is rebuilt during rest, and poor sleep works against it.

Signs to mention at your next visit, or sooner

Call the office if you notice any of these, rather than waiting:

Feeling weaker than before, or tiring much faster with ordinary tasks
Dizziness or lightheadedness
Losing weight much faster than expected, or being unable to eat enough
Noticeable hair thinning, which can follow rapid weight loss and is worth discussing

For other side effects and when to call, see GLP-1 Side Effects: What Is Normal and What Is Not.

After bariatric surgery, the same rule applies

Patients who have had weight loss surgery, and patients who use a GLP-1 medication after surgery, follow the same principles: protein first, strength training, and regular follow-up. A small number of patients can experience a slow weight regain over time, and keeping muscle is one of the best protections against it.

The bottom line

GLP-1 medications can be an effective tool, and losing some lean tissue along the way is not a reason to avoid them. It is a reason to use them with a plan. In Dr. Baptista's program, that plan includes an initial evaluation, medication when appropriate, monthly follow-up visits, and a dietitian, so strength is watched alongside the scale. Dr. Baptista uses a special scale that can measure your body composition. The goal is for approximately 80% of the weight you lose to be fat.

To ask about the program, call (904) 724-2263 or request a callback through the chat assistant on this website.

This article is for general education and is not a substitute for medical advice. Always follow the guidance of the physician who prescribes and monitors your treatment.

Please see our medical disclaimer.