Dr.PeteFamMed said:Body composition tracking via bioimpedance on lean mass (InBody scan every 3 months): Metric Baseline Month 3 Month 6 Month 9 Skeletal Muscle (lbs) 75…
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.
BenResearch_OR said:Right, and protein targets should be set on a reference weight rather than current weight.
Genuinely useful, thank you. I had the facts and not the framework. Adding it to my notes with a link back to this thread.
Dr.PeteFamMed said:Body composition tracking via bioimpedance on lean mass (InBody scan every 3 months): Metric Baseline Month 3 Month 6 Month 9 Skeletal Muscle (lbs) 75…
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.
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Shop Reference Standardslucas_SP_BR said:I lifted three times a week throughout and still lost lean mass.
DEXA scan update relevant to lean mass:
Scanned at months 0, 6, and 12. Here are the body comp numbers:
| Baseline | Month 6 | Month 12 | |
|---|---|---|---|
| Total mass | 260 lbs | 220 lbs | 197 lbs |
| Fat mass | 100 lbs | 80 lbs | 47 lbs |
| Lean mass | 153 lbs | 155 lbs | 154 lbs |
| Body fat % | 45% | 35% | 21% |
Lean mass preserved — actually GAINED 1-2 lbs thanks to progressive overload + 1.6g/kg protein. The lean mass discussion needs to include body comp data, not just scale weight.