Concerned about losing LEAN BODY mass? read on

[barbie]

Hi friends. I am happy to share the results of a deep dive I did on the topic of LEAN body mass (versus TOTAL body mass, which includes lean, fat, and a small amount of "other").

I was concerned about this topic after listening to a podcast with Dr Attia, where he showed data that his patients on glp-1 agonists where losing more LEAN body mass than FAT mass, which would be bad. We want to lose fat... and spare the muscles. His evidence for this data was DEXA (whole body imaging) scans, which can be inaccurate when differences in hydration levels occur. I wanted to see if he was correct, based on other, more rigorous studies (his wasn't a study - it was an observation of his patients, many of whom tend to be health enthusiasts).

So here are some studies I found, from PubMed (NIH). I am not sure how long posts can go in this forum, so I will post studies in the comments. Pay attention to which glp-1 the study covers, many are Tirz (my interest area) but some are Sema.

Lastly these are the notes I personally took. I might have interpreted incorrectly. I am not a medical professional, I am just a mom. Please check with your doctor if you have questions on this!

 

[barbie]

BACKGROUND INFO: the aim of weight management should be normalization of body *composition*, not just reduction of weight. It matters WHAT we lose. It is important to reduce excess abnormal FAT mass, without adversely affecting muscle and bone ("LEAN mass").

 

[barbie]

The Eli Lily SURMONT-1 trial with Tirzepatide, looked at visceral FAT loss vs. LEAN mass loss (want to preserve the latter as much as possible)

SUMMARY: Fat-to-lean mass ratio improved more with tirzepatide than placebo (this is good!)

RESULTS:
“… 160 patients had their body composition assessed at baseline and at 72 weeks… those on placebo lost 8.2% of their body FAT mass, versus 33.9% among those on Tirz"

Visceral FAT mass % change was 7.3% versus 40.1%, respectively.

LEAN mass loss was 2.6% versus 10.9%

Tirz showed a threefold greater reduction in FAT mass than LEAN mass, resulting in an overall improvement in body composition.

FAT mass as a proportion of overall body mass decreased from 46.8% to 44.7% with placebo, versus 46.2% to 38.5% with Tirz

Similarly, LEAN mass as a proportion of body mass increased from 50.7% to 52.4% with placebo, versus 51.0% to 58.1% with Tirz

LINK to study: https://www.practiceupdate.com/cont...-multiple-beneficial-metabolic-effects/142614

 

[barbie]

Semaglutide is similar, although Tirz may show advantages over Sema, as the quality of the weight loss with semaglutide 2.4 mg (highest dose) is good, but not as good as Tirz.

In STEP 1, DEXA scan data reported that there was mean loss of –8.36 kg of total body FAT mass and –5.26 kg of total body LEAB mass in the semaglutide-treated participants, versus placebo group –1.37 kg fat mass and –1.83 kg lean mass.

(Note, with "normal" regular weight loss, the usual proportion of LEAN loss (compared with total weight loss) is 25%.)

They discuss the LOOK AHEAD study, which compared intensive lifestyle interventions (ILI) to diabetes support and education (DSE) in persons with type 2 diabetes. As expected with weight loss, ILI led to greater reduction in FAT mass than DSE, but also greater loss of LEAN body mass during active weight loss. When ILI participants regained weight, they regained mainly FAT mass. In addition, there were greater decreases in bone density (hip and femoral neck) in ILI vs DSE at 1 year.

STUDY LINK: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8526285/

 

[barbie]

---

In tbis study, something stood out to me:

"observed reductions in LEAN body mass are mainly attributed to body water reduction" (this is important with DEXA scans… dehydration will impact greatly!)

STUDY LINK: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10092154/

 

[barbie]

Here is a study on a dual GIP/GLP-1 agonist, simialr to Tirz (but it is not Tirz!). This peptide did not cause LEAN body mass loss at the 28 day mark:
"a GIP/GLP-1- peptide, with characteristics of exendin-4, known for enhanced metabolic stability and reduced clearance with respect to (D-Ala2) GIP..... 4 hours post-injection benefit: reduced serum glucose and improved insulin secretory compared to controls...... At 28 days: HFF (high fat fed) mice: reduction of body weight, due to the loss of total body FAT, while no change in LEAN body mass was documented, plus: improving HbA1c, non-fasting blood glucose levels, and lipid profile, most likely due to enhanced insulin and β-cell insulin sensitivity when compared to the control group (saline). The hybrid peptide was able to act on the memory impairment associated with obesity-diabetes by improving it."

STUDY LINK: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8779403/

 

[barbie]

In this study on Semaglutide: "total LEAN body mass decreased from baseline (-9.7%); however, the proportion relative to total body mass increased by 3.0%-points. An increasing improvement in LEAN body mass:FAT mass ratio was seen with semaglutide with increasing weight loss from baseline to week 68 (continuous data). Overall, the ratio increased from baseline... to week 68 by 0.23, with greater improvement in those with ≥15% weight loss..."

"Conclusion: In adults with overweight or obesity, semaglutide 2.4 mg was associated with reduced total FAT mass and regional visceral FAT mass, and an increased proportion of LEAN body mass. Greater weight loss was associated with greater improvement in body composition (LEAN body mass:FAT mass ratio)."

STUDY LINK: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8089287/

 

[AJ-Inter]

Barbie, Thank you for posting this interesting and valuable data.

 

[FamousGoodkitty]

Great Studies, Thank you! Such helpful information for all of us to keep in mind.

 

[Tidalwave]

Based on what I’ve read, tirzepatide may cause some loss of lean body mass, but it seems to be a relatively small percentage of the overall weight loss.

Most of the weight loss with tirzepatide is fat mass. So, while there may be some lean body mass loss, it seems that the overall body composition improves with tirzepatide treatment.

This means that while you may lose some muscle mass, you will also lose more fat mass, leading to an overall improvement in your body composition.

from the studies I’ve seen, the impact on lean body mass is small and not considered a major concern. Additionally, some people may find that the weight loss achieved with tirzepatide can lead to increased physical activity levels, which may help to offset any small amount of lean body mass loss.

 

[ilovebubbles]

This is my (very non scientific, not an expert) thoughts on lean mass when it comes to dieting…
Why would our bodies go after our muscles (which is very expensive metabolically) for energy in a calorie deficit or while dieting or fasting if we have fat cells that have been stored for that express purpose? This comes up a lot in keto forums and fasting forums. I’ve dabbled in both for over 3 years now. I just have a hard time believing that our bodies would burn through muscle for energy at anywhere close to what it does with fat. Makes no sense. I read somewhere recently that muscle loss (seen on dexa scans during use of glp1’s) could probably be attributed to hydration levels, as opposed to being actual muscle loss.
Now, if someone is very lean already and does not have a lot of fat for the body to use for energy and they are fasting or in a calorie deficit, then yes…the body would be forced to start using muscle for energy.

 

[Cbeam13]

Wow! Great info! Thank you for sharing this.

 

[barbie]

Well there’s loads of published studies saying that our bodies do not discriminate against what fuel sources it uses (I.e. body fat vs muscle). It’s not a matter of believing or not, it’s an established fact, which is why we have to exercise.

did you read the studies I posted above? you contradict the studies. the body does indeed "discriminate" and with Tirz especially, it will preferentially burn FAT. it will even burn fat at a faster rate than muscle, which improves body composition ratios!

you are correct about exercising - it will further improve that ratio.

 

[Scorpio73]

GLP-1 meds do NOT cause muscle loss or have any sort pf mechanism that would do so. Eating too little and to little PROTEIN causes muscle loss.

We have now seen that glp-1 meds should infact make muscle gain/preservation EASIER...but people just don't attempt to get their protein in.

This has nothing to do with the drug causing muscle loss. It's lack of protein and calories.

GLP-1 agonists improve glucose absorption in muscle as well as decrease muscle atrophy attributes of the cell/muscle..Decrease effects of *myostatin*!!.....Decreases atrogin-1 (which breaks down muscle)

When improving insulin sensitivity then you improve what insulin does in protein synthesis. You will gain or at the least keep muscle!

So yes, it's lack of the building blocks; protein/aminos causing LBM loss.

Get in the protein and not starvation kevel calories, and you won't lose muscle.

 

[barbie]

Wow! Great info! Thank you for sharing this.

you are so welcome

GLP-1 meds do NOT cause muscle loss or have any sort pf mechanism that would do so. Eating too little and to little PROTEIN causes muscle loss.

We have now seen that glp-1 meds should infact make muscle gain/preservation EASIER...but people just don't attempt to get their protein in.

This has nothing to do with the drug causing muscle loss. It's lack of protein and calories.

GLP-1 agonists improve glucose absorption in muscle as well as decrease muscle atrophy attributes of the cell/muscle..Decrease effects of *myostatin*!!.....Decreases atrogin-1 (which breaks down muscle)

When improving insulin sensitivity then you improve what insulin does in protein synthesis. You will gain or at the least keep muscle!

So yes, it's lack of the building blocks; protein/aminos causing LBM loss.

Get in the protein and not starvation kevel calories, and you won't lose muscle.

interesting about myostatin and atrogin-1

do you by any chance have any source links (PubMed etc)?

 

[PeppyLaPep]

did you read the studies I posted above? you contradict the studies. the body does indeed "discriminate" and with Tirz especially, it will preferentially burn FAT. it will even burn fat at a faster rate than muscle, which improves body composition ratios!

you are correct about exercising - it will further improve that ratio.

Here’s one of many studies that say GLP-1 agonists do in fact cause muscle loss. While I definitely agree that we need to continue to eat a lot of Protein and like I said, we have to exercise, there are lots of articles and studies that say with any kind of weight loss, you’re going to lose muscle too. I am not trying to argue, but if you focus on making sure to keep your muscles healthy, fed and working, you will have less muscle loss and instead lose more fat. To quote this article: “Initial body composition data from a short-term (12-week) Semaglutide treatment observed a 5kg change in body mass, with 70% (3.5kg) of that from fat mass and 22% (1.1kg) from lean mass [14].”

Don’t shoot the messenger, all I’m saying is that with all weight loss, you will lose a combination of both fat and muscle. The trick is to make sure to focus on maintaining your healthy muscle mass. It’s not a cure all targeting only fat. You have to be healthy; exercise, upping your protein, etc. It does not only target fat. Have a great & healthy weekend.

https://gethealthspan.com/blog/arti...st-drugs-on-lean-mass/6veix8haommeyhv6eecx3s/

 

[westby]

It seems the various participants in this discussion are trying to compare as many as five (or more?) distinct things:
Total Lean Mass Loss
Lean Mass Loss as % of Weight Loss
Total Muscle Loss
Muscle Loss as % of Weight Loss
Change in Body Composition

Lean mass includes everything in your body other than fat. Yes, muscle. Also water, bones, blood, skin, etc. It is a rather vague and variable health measure. A drop in lean mass could mean a good or bad change. For example, edema (water retention) can increase lean mass; that doesn't mean you are healthier for it. Losing that lean mass is likely healthy.

Muscle mass is just muscle. This measure is most useful as a % of current body weight. Losing muscle mass isn't necessarily a bad thing, either; it can be neutral or even good for joints and heart in some cases. If you needed extra muscle to walk around in a 350 pound body, as you lose weight, you don't have the same need for it. It is also possible to lose some total muscle mass while seeing your % muscle mass *increase*. Yay math!

When people say research shows GLP-1s don't cause muscle loss, what they usually mean is *extra* muscle loss (as a % of total loss) compared to people who lose weight without GLP-1s. The study mentioned above, for example, showed that tirzepatide 15mg protected about 7 grams of protein from being used for energy and increased fat use by about 15 grams per day. So a person on tirzepatide will likely lose somewhat less muscle during weight loss than a person with similar food intake & activity level who isn't on tirzepatide. This does not mean they will lose zero muscle.

The takeaway should be that every person losing weight ought to educate themself about healthy body composition, including muscle mass %, and monitor regularly if possible. Unwanted muscle loss can be minimized or reversed through adequate protein, resistance training, and slower weight loss.

 

[PeppyLaPep]

It seems the various participants in this discussion are trying to compare as many as five (or more?) distinct things:
Total Lean Mass Loss
Lean Mass Loss as % of Weight Loss
Total Muscle Loss
Muscle Loss as % of Weight Loss
Change in Body Composition

Lean mass includes everything in your body other than fat. Yes, muscle. Also water, bones, blood, skin, etc. It is a rather vague and variable health measure. A drop in lean mass could mean a good or bad change. For example, edema (water retention) can increase lean mass; that doesn't mean you are healthier for it. Losing that lean mass is likely healthy.

Muscle mass is just muscle. This measure is most useful as a % of current body weight. Losing muscle mass isn't necessarily a bad thing, either; it can be neutral or even good for joints and heart in some cases. If you needed extra muscle to walk around in a 350 pound body, as you lose weight, you don't have the same need for it. It is also possible to lose some total muscle mass while seeing your % muscle mass *increase*. Yay math!

When people say research shows GLP-1s don't cause muscle loss, what they usually mean is *extra* muscle loss (as a % of total loss) compared to people who lose weight without GLP-1s. The study mentioned above, for example, showed that tirzepatide 15mg protected about 7 grams of protein from being used for energy and increased fat use by about 15 grams per day. So a person on tirzepatide will likely lose somewhat less muscle during weight loss than a person with similar food intake & activity level who isn't on tirzepatide. This does not mean they will lose zero muscle.

The takeaway should be that every person losing weight ought to educate themself about healthy body composition, including muscle mass %, and monitor regularly if possible. Unwanted muscle loss can be minimized or reversed through adequate protein, resistance training, and slower weight loss.

Hi Barbie, we are basically agreeing here, with the one exception that muscle mass is indeed lost, along with fat. It’s not a biggie; I also don’t care to argue at all! I love GLP-1 agonists & also LOVE staying healthy! Take care.

 

[barbie]

Here’s one of many studies that say GLP-1 agonists do in fact cause muscle loss. While I definitely agree that we need to continue to eat a lot of Protein and like I said, we have to exercise, there are lots of articles and studies that say with any kind of weight loss, you’re going to lose muscle too. I am not trying to argue, but if you focus on making sure to keep your muscles healthy, fed and working, you will have less muscle loss and instead lose more fat. To quote this article: “Initial body composition data from a short-term (12-week) Semaglutide treatment observed a 5kg change in body mass, with 70% (3.5kg) of that from fat mass and 22% (1.1kg) from lean mass [14].”

Don’t shoot the messenger, all I’m saying is that with all weight loss, you will lose a combination of both fat and muscle. The trick is to make sure to focus on maintaining your healthy muscle mass. It’s not a cure all targeting only fat. You have to be healthy; exercise, upping your protein, etc. It does not only target fat. Have a great & healthy weekend.

https://gethealthspan.com/blog/arti...st-drugs-on-lean-mass/6veix8haommeyhv6eecx3s/

I am not sure you read my posted studies carefully?

The study you posted is about Sema, by the way. My posts above show that Tirz is even better than Sema for losing more fat mass than lean mass. But *both* glp-1's are good. The study you posted did not disprove that.... but you think it does, it sounds like.

I am not sure how we are not coming to the same conclusion but I am willing to walk you through things, if you like.

 

[barbie]

tl;dr: it is possible that the concept of "ratio" (lean:total mass lost, and fat:total mass lost) is throwing you off. If so, that would absolutely skew the study "conclusions" for you.

-----

You may be conflating what my posts say, with something different.

In fact, the studies I posted state (in *multiple* places, no less!) that both lean mass and fat mass are lost, when losing weight. Of course. You knew that too, I believe.

But the *ratio* of loss is very favorable to some degree muscle preservation, over fat. I think this is where you may get lost (with the "ratios"), and not understand just how they work, and what they mean. (And how we can emeliorate that ratio even more - as Westby pointed out above - with protein intake, weight-bearing exercise, etc).

I think you might truly benefit from going through the studies with a fine toothed comb, using an online medical dictionary, and taking notes. Especially what the fat mass: total mass ratio means - and how it changes with "normal" weight loss and with glp-1's (esp Tirz)