Comment by crazygringo
2 months ago
I'm always so baffled by warnings about losing muscle when losing weight.
Of course you do! If your body is tens of pounds lighter, then you don't need the extra muscle to lug it around. This paper is about reduction in heart muscle, and of course your heart doesn't need to be as strong because there's less blood to pump and less tissue to fuel.
When you gain weight, you also increase the muscles needed to carry that weight around. If you see someone obese at the gym doing the leg press, you may be astonished at how strong their legs are. When you lose weight, you don't need that muscle anymore.
Our bodies are really good at providing exactly the amount of muscle we need for our daily activities (provided we eat properly, i.e. sufficient protein), so it's entirely natural that our muscles decrease as we lose weight, the same way they increased when we gain weight. Muscles are expensive to keep around when we don't need them.
Obviously, if you exercise, then you'll keep the muscles you need for exercising.
But this notion that weight loss can somehow be a negative because you'll lose muscle too, I don't know where it came from. Yes you can lose muscle, but you never would have had that muscle in the first place if you hadn't been overweight -- so it's not something to worry about.
From the article: "...explains this rate of muscle decline is significantly higher than what is typically observed with calorie-reduced diets or normal aging and could lead to a host of long-term health issues..."
The warning isn't that you're losing muscle during weight-loss with these drugs. It's that the ratio of muscle vs fat loss is much greater with the drugs compared to traditional weight loss methods.
It's been well studied that if you exercise and eat enough protein while losing weight, you can retain more muscle.
Losing a lot of lean mass is incredibly detrimental to your longevity and quality of life.
Even amongst traditional calorie deficits, rapid weight loss results in greater loss of muscle mass when compared to gradual weight loss, even if you lose the same amount of mass overall. I.e. you keep more muscle losing 0.5 lbs a week over 40 weeks than 2 lbs a week over 10 weeks.
> Even amongst traditional calorie deficits, rapid weight loss results in greater loss of muscle mass when compared to gradual weight loss,
This does not make any sense. Why would the body prefer anything over the most dense and available calorie store? Protein in muscle gives shit calories per gram, it is hard to build back and generally less available than fat: the number one energy store, doing exactly what it does.
11 replies →
Can you provide a single high quality (randomized) study demonstrating GLP1 therapeutics are 'incredibly detrimental to [your] longevity and quality of life'?
Consider the type of confounding that occurs in studies of people losing a lot of lean mass: cachexia, restriction to bed, famine.
Traditional weight loss methods have not shown the magnitude of survival benefits wrt cardiovascular disease, joint pain, diabetic complications. Exercise is wonderful, but as a public health intervention it is not sufficient.
If anyone looks at the totality of the high quality GLP1 clinical evidence and concludes these drugs are going to cause a net reduction in longevity and quality of life, then they should step back and assess their process for evaluating information.
Exercise is a public health intervention that actually works in improving health. It may not work to create actual weight loss, but it does improve things like blood pressure regardless.
>>>Losing a lot of lean mass is incredibly detrimental to your longevity and quality of life.
While true, its also true that if you manage to lose substantial fat in the process, it leads to longer and better quality life
> it leads to longer and better quality life
This needs a slight change in wording or clarification, depending on what you meant.
Losing substantial fat when overweight increases your chance of a longer and better quality life than if you had maintained high levels of fat. Losing substantial muscle in that process reduces your chances of the same. It's statistics and never guaranteed.
If I'm reading the study [1] correctly, that conclusion is not warranted.
It appears that they fed the control group and treatment group of mice lots of food to get them fat, then gave them identical normal diets, and gave the treatment group semaglutide.
The semaglutide group lost significantly more weight (fig A.ii) than the control group, and also lost heart muscle.
So it does not seem that they compared to an equivalent amount of weight loss in mice, which is what I'd think you'd need to do to come to the conclusion from the article (actually, not just an equivalent amount of weight loss, but also at the same rate).
[1] https://www.sciencedirect.com/science/article/pii/S2452302X2...
I guess perhaps the better conclusion would be that maybe dosages should be adjusted so that people don’t lose weight too quickly?
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> Our bodies are really good at providing exactly the amount of muscle we need for our daily activities
The problem is that the average joe's daily activity is incompatible with an healthy muscle mass. After 30 if you don't actively exercise you lose muscle mass, if you're obese, 50 and starve yourself or take drugs that make you lose more muscles than necessary you won't gain them back ever unless you do some form of serious resistance training
https://hips.hearstapps.com/hmg-prod/images/triathlete-aging...
Some years ago there was a crazy science exhibit going around museums in the US that had human cadavers preserved with some plasticizing process where you could see different tissues. They also had cross sections.
They actually had an exhibit showing the effects of obesity on tissues. This was before fat acceptance became a thing. That was really an eye opening exhibit showing shrunken muscle tissue, shrunken hearts, shrunken/squeezed lungs, etc.. in obese people.
Kind of opened my eyes as to how crazy the changes are.
You're describing it backwards.
Obesity tends to cause heart enlargement (https://radiopaedia.org/articles/obesity-cardiomyopathy), larger muscles (as you're doing essentially built-in weight training just walking around), and organs don't tend to shink; cross-sections show a pretty similar body cavity (https://www.cultofweird.com/medical/human-body-slices/) - the fat largely goes on top of it.
It was a really great exhibit, watch a smoker regret his life choices in real-time when given the chance to hold a lung taken from a smoker.
I believe you are thinking of 'Body Worlds' [1]
[1]: https://bodyworlds.com/
I'm not qualified to interpret results, but this paragraph stuck out to me:
> Using mice for the study, the researchers found that heart muscle also decreased in both obese and lean mice. The systemic effect observed in mice was then confirmed in cultured human heart cells.
So it also happened for already lean mice (though no mention of whether they still lost fat), and for cultured human heart cells (so not a by-product of needing less muscle to pump blood through a shrunken body).
> Our bodies are really good at providing exactly the amount of muscle we need for our daily activities
That is exactly the risk. Our bodies are really good at it. But we are taking drugs that may change what our bodies do. Even a small bit of extra heart muscle loss may push as below where our bodies would have left us naturally. Is that dangerous? Are there people who need to worry about it? How do we know whether or not that should be a concern? It raises questions, and is worthy of discussion, even if we do land at answers that say it is an acceptable level of risk.
I wondered about exactly this.
The study is actually a published letter [1], and it doesn't appear to account for this. Science Direct even published a study about this in 2017 [2]:
> Weight loss, achieved through a calorie-reduced diet, decreases both fat and fat-free (or lean body) mass. In persons with normal weight, the contribution of fat-free mass loss often exceeds 35% of total weight loss, and weight regain promotes relatively more fat gain.
We already know how to reduce the effect of this, the person simply needs to increase exercise as the weight is lost in order to maintain lean muscle mass.
[1] https://www.sciencedirect.com/science/article/pii/S2452302X2...
[2] https://www.sciencedirect.com/science/article/pii/S216183132...
Meta comment here, but Science Direct is an aggregator, and it doesn't make sense to talk about it as publishing. Elsevier published the referenced work in the journal "Advances in Nutrition", vol 8, issue 3, pp. 511-519.
When you gain weight, you also increase the muscles needed to carry that weight around. If you see someone obese at the gym doing the leg press, you may be astonished at how strong their legs are. When you lose weight, you don't need that muscle anymore.
Anyone can put up impressive #s on a leg pres. Try the bench press instead. No one impressed by leg press.
In regard to the oft claim of obese people being stronger or more muscular, not really. Studies show that obese people carry only a tiny extra 'lean body mass' compared to non-obese people when matched for height, age, and gender, and much of this extra mass is organs, not muscle. Otherwise, the extra weight is just water. Sometimes it is even less because obesity impairs movement, leading to muscle loss due to inactivity.
If obese people seem strong it is because the fat reduces the range of movement for certain lifts like the squat and bench press, so it's possible for obese people to put up impressive numbers owing to having to move the weight less distance. Same for pushing movements, e.g. linemen, as being heavier means more kinetic energy, but this is not the same as being stronger in the sense of more muscle output. This is why obese people are not that impressive at arm curls or grip strength relative to weight, but wirey guys can curl a lot relative to weight or have a lot of grip strength. An obvious example of this is overweight women having worse grip strength compared to men; the extra fat does nothing.
I don't mean to target your comment specifically because it's obvious you know the difference, but I'm continually annoyed by the conflation of fat and muscle as "weight," even by medical professionals who should know better.
We should not be talking about losing "losing weight" as a substitute for saying "losing fat," which is what most people mean. Likewise, when people say they want to "gain weight", they almost always mean they want to "gain muscle."
Why does this matter? Trying to manage one's health or fitness as "weight" gives (most) people the wrong idea about what their weight number represents, and what to do to improve their level of fitness and dial in on the anatomically appropriate amount of body fat. As an example, it's possible (although admittedly unlikely) for one to work hard to gain muscle and strength while reducing body fat and stay exactly the same weight the whole time. Their overall health, fitness, and longevity will be significantly improved but pop fitness will tell them that they haven't made any progress at all.
The other thing is conflation between health and fitness. If you are below overweight range, no matter where you are, loosing additional fat is unlikely to make you healthier.
At some level of fat, which is actually more then "thin", you are perfectly fine. Further weight loss is about aesthetic or athletic performance, but has zero effect on health or even slight negative estimated health effect.
That doesn't strike me as a real problem.
Everybody already understands that "losing weight" means losing fat, not muscle. They don't leave the doctors office after a weight warning thinking they need to stop going to the gym.
Likewise, nobody is scared of gaining muscle because they think it will be bad for their health.
> When you gain weight, you also increase the muscles needed to carry that weight around.
I can't figure out how relevant that is. From what I've seen of obese people they always struggle with limited mobility, which often only improves with physiotherapy (or other forms of exercises). Sumo wrestlers are huge but can move faster than an equivalent obese person because (I assume) they have stronger muscles due to their regular regimented training and diet. Does this mean they have more muscle mass than fat compared to an equivalent obese person? Does more muscle mass indicate stronger muscles?
Well, based on my DEXA scan from before I started on tirzepatide, if I had dropped to 20% BF with my starting LBM, I would have been in close to the best shape of my life. I certainly have a lot of extra muscle in my legs from carrying my fat ass around.
> Does more muscle mass indicate stronger muscles?
Yes. Strength for specific movements involves CNS adaptation, but if you look at the top tier of powerlifters, ranking them within a weight category by MRI muscle mass would produce basically identical results to their actual rankings.
And obviously the heart is going to reduce muscle now that it doesn't need to pump blood through heaps of fat.
Then a study concentrates no comparing muscle weight loss by traditional dieting, that is a change in what someone eats, to weight loss via drugs.
It is not immediately clear if the muscle loss happens faster (probably) what the immediate impact of that is, and whether or not you lose more muscle mass on one or the other.
What they need is to design some sort of mouse gym.
MouseLifts 5x5 + RAtkins diet
"Gym rats" was already a thing.
I'm always so baffled by people commenting without reading the article first.
> "Please don't comment on whether someone read an article."
https://news.ycombinator.com/item?id=42204741