The Podcast by KevinMD Why measuring muscle mass matters more than tracking your weight
Mar 24, 2026
Maureen McBeth, a physical therapist and lymphedema specialist with 25+ years in oncology rehab, champions body composition over the scale. She discusses risks of rapid weight loss from GLP-1s, why losing muscle is dangerous, and the need for muscle, fat, and fluid testing. She also covers practical monitoring, clinical vs. home bioimpedance, and strength-focused exercise to protect muscle.
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Clinician's Personal GLP-1 Journey
- Maureen McBeth shared her personal experience: after major facial reconstruction she gained weight, then started a GLP-1 while monitoring body composition.
- She used bioimpedance spectroscopy and feared muscle loss seen in many patients, which motivated her article and self-tracking.
GLP-1 Weight Loss Can Destroy Muscle Mass
- Rapid weight loss on GLP-1s often reduces skeletal muscle mass, leaving high body fat and a depleted metabolic engine.
- Maureen observed patients losing large amounts of weight but showing very low muscle and disproportionately high fat on body composition tests.
Measure Body Composition Not Just Weight
- Test body composition before and during GLP-1 treatment rather than relying on BMI or the scale.
- Maureen recommends measuring muscle, intracellular water, and balanced extracellular water with bioimpedance to protect metabolic health.