Peloton + GLP-1 community — looking for input

DeniseRN_TPA said:

Back pain as a lean mass side effect: not from the medication itself, but from rapid body composition changes.

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.

DataDave said:

Agreed on the ranges, with the condition that a single DEXA is not a measurement, it is one draw from a distribution.

Saving this. It is the first explanation that did not require me to already understand it. I will report back once I have actually tried it.

DeniseRN_TPA said:

Back pain as a lean mass side effect: not from the medication itself, but from rapid body composition changes.

Bone density monitoring on lean mass: DEXA bone density at baseline and month 12.

Lumbar spine T-score: -0.9 → -0.7 (stable to slightly improved)
Femoral neck T-score: -0.12 → -0.8 (stable)

No significant bone loss despite 71 lbs of weight loss. Key factors: adequate calcium (1200mg/day), vitamin D (5000 IU/day), resistance training 3x/week, and adequate protein. Weight-bearing exercise is critical for maintaining bone density during rapid weight loss.

hans_munich said:

I lifted three times a week throughout and still lost lean mass.

hans_munich said:

...the muscle loss concern with lean mass...

This is a legitimate and well-studied concern. Let me put some numbers on it:

In STEP 1, approximately 39% of weight lost was lean mass. However, the Lundgren 2024 study showed that structured resistance training reduced this to ~25% lean mass loss.

Context matters: at BMI 35+, you're carrying excess lean mass to support the extra weight. Losing some lean mass is expected and not inherently harmful if you maintain adequate muscle function through exercise.

The solution isn't avoiding the medication — it's combining it with proper exercise and protein intake.

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