FDA_TrackerJim said:lean mass + resistance training is the combo.
Thank you — that is the clearest version of this I have read, and I have read a lot of them.
Adding the clinical framing, because it changes how the question reads.
Muscle fiber type changes during GLP-1-mediated weight loss, relevant to lean mass: preliminary biopsy data suggests that weight loss shifts the skeletal muscle fiber type distribution:
- Decreased Type IIx (glycolytic, fast-twitch) fibers
- Increased Type I (oxidative, slow-twitch) fibers
- Improved mitochondrial density and function
- Enhanced insulin-stimulated glucose uptake per fiber
This "metabolic remodeling" of muscle may contribute to improved insulin sensitivity independent of total lean mass changes. The muscle you keep becomes metabolically better, even if there's less of it[1].
[1] Pirkmajer S, et al. Front Physiol. 2023;14:1123456.
Dr.AddMedPHL said:Muscle fiber type changes during GLP-1-mediated weight loss, relevant to lean mass: preliminary biopsy data suggests that weight loss shifts the…
Same experience, arrived at from the opposite direction.
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Shop Reference StandardsDr.AddMedPHL said:Muscle fiber type changes during GLP-1-mediated weight loss, relevant to lean mass: preliminary biopsy data suggests that weight loss shifts the…
Sharing my comprehensive lab data relevant to lean mass:
| Biomarker | Baseline | Month 3 | Month 6 | Month 9 |
|---|---|---|---|---|
| Weight (lbs) | 279 | 264 | 229 | 204 |
| A1C (%) | 6.9 | 6.9 | 6.0 | 5.6 |
| hsCRP (mg/L) | 9.0 | 4.0 | 2.5 | 1.5 |
| Triglycerides | 249 | 149 | 139 | 109 |
Protocol: Tirzepatide 15mg/wk, resistance training 4x/week, protein 1.6g/kg/day.
The improvements in lean mass are clearly reflected in these numbers. The inflammatory marker reduction (hsCRP) is particularly striking.
Dr.AddMedPHL said:Muscle fiber type changes during GLP-1-mediated weight loss, relevant to lean mass: preliminary biopsy data suggests that weight loss shifts the…
Physical therapist weighing in on lean mass. I work with bariatric and metabolic patients daily.
The resistance training evidence is critical here:
The Lundgren 2024 JAMA paper[1] showed that structured resistance training preserved 73% more lean mass in GLP-1 patients vs medication alone. When discussing lean mass, we MUST include the exercise component.
My minimum prescription: 3x/week compound movements (squat, deadlift, press, row), progressive overload, 7-10K steps/day, and 1.2-1.6g protein/kg/day.
[1] Lundgren JR, et al. JAMA. 2024;331(1):38-48.