GLP-1s helped me lose 70 pounds — but up to 40% was muscle, not fat. Why isn’t anyone talking about this?
I hit my goal weight last month after 14 months on tirzepatide and I was SO proud. Then I got a DEXA scan because my trainer recommended it and honestly I’m kind of devastated. Started at 242 pounds, now at 172. That’s 70 pounds gone which sounds amazing right? But the scan showed I lost about 28 pounds of lean muscle mass. That’s 40% of my total weight loss.
My doctor acted like this was totally normal and just said to “make sure you’re getting enough protein” but like… nobody mentioned this before I started? All the success stories are about the number on the scale. I feel weaker than I did before, my resting metabolic rate dropped significantly, and now I’m reading that this muscle loss might make it easier to regain all the weight back.
I wasn’t completely sedentary either – I was walking 4-5 times a week and doing some light resistance bands. Apparently that wasn’t enough? Has anyone else actually measured their body composition during their GLP-1 journey? What did you find? And more importantly, is there any way to reverse this or am I just stuck with less muscle mass now?
This is EXACTLY why I keep preaching about resistance training on here. The studies on this are actually pretty clear – GLP-1s don’t distinguish between fat and muscle when you’re in a caloric deficit. I lost 45 pounds on semaglutide but I was lifting heavy 3-4x per week the entire time and my muscle loss was only about 15% of total weight lost according to my InBody scan. Still not ideal but way better than 40%. Your walking and resistance bands unfortunately probably weren’t enough stimulus to tell your body to preserve that muscle. The good news is you can rebuild it but it takes time and real strength training. Definitely worth working with a trainer who understands this stuff.
ugh this is my biggest fear. I’m 6 weeks into tirz and down 18 pounds but I have NO idea how much is muscle vs fat. My doctor never brought this up either and I’m kind of annoyed about that tbh. Did your insurance cover the DEXA scan or did you pay out of pocket? I really want to get one now before I lose more weight so I at least have a baseline to compare to later.
How much protein were you actually eating though? Because I see a lot of people on these meds barely hitting 60-70g a day because of the appetite suppression and then wondering why they’re losing muscle. The general recommendation I’ve seen is like 0.7-1g per pound of goal body weight MINIMUM when you’re on GLP-1s, plus the resistance training that ResistanceIsKey mentioned. I’m 42M and I’ve been militant about tracking my protein (averaging 140-160g daily) and doing full body workouts twice a week. Down 32 pounds in 5 months and just got my second DEXA – lost about 22% muscle which still isn’t great but my doctor said it’s actually on the better end of what she sees with her GLP patients.
This is one of those things that makes me really frustrated with how these medications are being prescribed. Doctors are handing them out like candy but not giving people the full picture about body composition changes. Yeah you’ll lose weight but at what cost? I read somewhere that muscle loss during rapid weight loss can affect bone density too over time. Not trying to scare you OP but definitely worth having a real conversation with your doctor about whether continuing is right for you, and maybe getting a referral to a registered dietitian and physical therapist who can help you rebuild what you lost safely.