Weight loss with GLP-1 medicines does not result in a disproportionate loss of muscle mass or function

[RetCurious]

Summary

The large decrease in body weight with glucagon-like peptide-1 (GLP-1) medicines raises concern about a loss of lean body mass (LBM) and skeletal muscle. In this work, we present four pre-clinical studies and a proof-of-concept clinical trial that address this issue. We report that in obese mice, GLP-1 medicines predominantly reduce body fat alongside a small but significant decrease in LBM. Among lean tissues, loss of liver mass exceeds change in muscle mass. While absolute muscle mass and strength decrease, relative muscle mass and strength improve, resulting in better running performance. Interestingly, while atrophy is similar during immobilization, GLP-1 medicines have a distinct effect on the muscle proteome compared to calorie restriction. Patients with obesity on GLP-1 medicines improve their body composition without negatively affecting strength. Overall, in middle-aged mice and men, GLP-1 medicines slightly decrease absolute muscle values but positively impact body composition and mobility.

https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(26)00082-0#

 

[Devilseye]

Great news! I mean Ive been strength training for decades and I dont notice a loss of LBM beyond what would be expected from calorie restriction. Quite minimal overall. I have lost strength though but my musculature is still there.

 

[RetCurious]

Makes me wonder if the "extra protein" advise still hold up...

 

[sheilarae74]

I have actually seen more muscle growth while on reta than I have the entire year previous. I don't know if it has anything to do with better body recomp with reta or is it because I was on keto that year and now I am getting more carbs and protein. I sure don't seem to be losing any muscle and I am only been doing light weight training this whole time.

 

[woundcarping]

Makes me wonder if the "extra protein" advise still hold up...

How so?

I've had two DEXA scans, 1/30 and 3/25. According to the scans I lost 18.7lb with .5lb of that was lean mass. That's inside the tolerances of the scan, for example they also said I lost 100g of bone mineral content and put on 155g of visceral fat covering 17% more area... neither are very likely.

 

[RetCurious]

How so?

The focus on higher protein intake revolves around preventing loss of muscle mass, no?

If muscle mass loss is less of a concern does it follow that higher protein intake is less of a concern?

Yes, I'm still struggling to get my "recommended protein intake".

I like protein in my meals but I prefer balancing meals out with fruits and vegetables.

On reta I find I'm even more inclined toward fruits and veggies.

 

[woundcarping]

The focus on higher protein intake revolves around preventing loss of muscle mass, no?

If muscle mass loss is less of a concern does it follow that higher protein intake is less of a concern?

Yes, I'm still struggling to get my "recommended protein intake".

I like protein in my meals but I prefer balancing meals out with fruits and vegetables.

On reta I find I'm even more inclined toward fruits and veggies.

People parrot daily protein targets of 1g/lb of body weight that they've heard without doing any research for themselves. Some say it's your current weight, while others say it's your target weight.

At 1g/lb current weight, I'd be expected to consume 240g of protein a day, every day. That's 2.3lb of ribeye or 12x 5oz cans of tuna, every day. There's no way my muscles can benefit from 240g of protein every day.

I have 153lb of lean mass, from that my daily minimum is 130g/day with the max being ~220g/day. My target is 150+g/day. I don't stress out if I go over my max, it's just practically wasted and not worth effort. I try to not go under my floor with any regularity, but it happens.

In the theme/theory of catabolic protection, I do the following:

Reta- over Tirz for the theorized lean mass sparing

TRT- clinical hypogonadal, started TRT ~5 weeks into my cut.

beta‑hydroxy beta‑methylbutyrate (HMB-FA)- 3g/daily

Resistance training-hit or miss, I've mainly missed over the past month, need to get back to the gym regularly.

D3k2-7- supplement, labs showed I was low, can affect training performance

With that general regimen according to DEXA scans, from 1/30 to 3/25 I lost 18.7lb with only .5lb of that being lean mass.

I'll be adding creatine in the next couple weeks after my water change stabilizes from changing my test dose based on labs. The plan is my next DEXA will be late next month.