[storus]

Isn't GLP-1 creating a "feel-good" starvation? Patching the receptors telling the brain one is not hungry and then just letting the body starve happily, leading to significant muscle loss and aged face? Contrary to e.g. water fast where the body switches to 100% ketosis that can run as long as there is any fat in the body and one supplements electrolytes (Mg/K/P/HCO3) and vitamins (predominantly B1/B2/B3), leading to a much more healthy appearance?

[rootusrootus]

GLP1s do not themselves cause any worse muscle loss than you would experience if you lost the weight by watching calories the old fashioned way.

"Ozempic face" is almost certainly an artifact of people who spent their life significantly overweight having somewhat looser skin than they would if they had maintained a low weight throughout their life.

Also, not everyone gets the face effect, not by a long shot.

[gedy]

Yeah exactly, what people call Ozempic Face is often just wrinkles. I look a bit older now that I lost 40 lbs, but much healthier shape. Fat does fill in your face some

[storus]

Not really, Ozempic face is the same face as one gets when starved of food for a longer period of time from low caloric diet that contains carbs. Ketosis on the other hand doesn't cause this unless one has almost no fat left as it doesn't switch body to the starvation mode.

There are two modes the human body operates normally - insulin-driven, active when carbs are in the food, and ketone-driven, active when there is a lot of fat storage and no food intake, or food has no carbs. Insulin-driven operation switches to starvation when food intake has caloric deficit but still enough carbs for insulin to be triggered; ketones on the other hand lead to zero insulin activity and pure fat burning; starvation is only activated when humans reach around 4% body fat while in ketosis.

[cthalupa]

This is a bunch of pseudoscience.

"Starvation mode" as people talk about it is generally nonsense - the exceedingly low bodyfat you mention for keto is the same place you would see it in a non-keto diet when we talk about actual starvation mode and not whatever you're talking about with a non-ketogenic diet.

The only real difference when it comes to the biology here is that fat mobilization into glucose is significantly slower and less efficient, which keeps your blood sugar levels more constant, which results in fewer post-meal food cravings. Which isn't nothing, but it's not muscle sparing in and of itself.

We have plenty of studies here. Keto diets are not better for sparing lbm.

https://pubmed.ncbi.nlm.nih.gov/38934469/

In fact, if you already have significant muscle mass, it might be worse. Glycogen is hugely important when doing resistance training, and keto significantly impacts your glycogen stores. People perform worse with their resistance training on keto than regular diets.

https://pmc.ncbi.nlm.nih.gov/articles/PMC9244428/ https://pmc.ncbi.nlm.nih.gov/articles/PMC8469041/

[storus]

I suspect you have no idea that your body has two independent energetic circuits - one driven by insulin and glucose, the other driver by ketones. Just please dump this to any decent LLm to give you ELI5. Muscles obviously need glucose for their best performance which is why strength training is not recommended during ketosis; OTOH ketosis is naturally muscle-sparing.

[cthalupa]

> I suspect you have no idea that your body has two independent energetic circuits - one driven by insulin and glucose, the other driver by ketones.

I am fully aware - I have spent several years of my life following a ketogenic diet. None of that is relevant for "starvation mode" and insulin within that context. I was replying to your specific points - not providing an explanation on how ketosis works from end to end.

Unless you are claiming that your body just doesn't produce glucose/glycogen and insulin when in ketosis? Which would also be incorrect.

> Muscles obviously need glucose for their best performance which is why strength training is not recommended during ketosis;

Strength training should 100% still be done in ketosis/while following a ketogenic diet. It will be suboptimal compared to a regular training, but being in ketosis doesn't magically make resistance training optional if you want to be healthy.

> OTOH ketosis is naturally muscle-sparing.

It is not and the study links in my post show consistent data here. There might be an exception if you are an endurance athlete but that is based on far more limited data than the rest of the research. So... if you're a high level endurance athlete that is also somehow fat, keto might be a better option when it comes to sparing muscle, but for the rest of us, not the case.

[storus]

You keep mixing normal carbohydrate metabolism with functional starvation mode when in low caloric high carb diet, i.e. elevated insulin in a low-energy/tired mode with increased cortisol, ramping up gluconeogenesis from muscle tissue, catabolic state from elevated stress hormones, T3 thyroid hormone underproduction, adrenaline spikes leading to insulin resistance beta-andregenic sensitivity downregulation, none of which is present in ketosis from e.g. water fasting.

As for ketosis sparing muscles that comes from a wide range of effects like low insulin, preserved/increased GH/IGF-1, BHB-inhibited muscle proteolysis and low leucine oxidation.

https://pubmed.ncbi.nlm.nih.gov/41035089/

Your super confident attitude is likely going to lead nowhere for any people following your advice and when they confront you about not reaching any fat loss goals, your response will be likely "it's you", instead of understanding the gaps in your own knowledge.

[cthalupa]

Muscle loss is determined by your protein intake, muscle stimulus, and rate of weight loss. Plenty of people start lifting for the first time (or after having stopped for extended periods of time) when going on GLP-1s and actually put on muscle mass.

It might result in more loss of buccal fat than otherwise but even that is not definitive. Activating the receptors is not the same as burning fat - there are GLP-1 receptors all over your body in all sorts of organs. If you activate them in your brain you're not burning your brain for energy.

[warmedcookie]

n=1, been lifting weights for 25 years and lost 40 lbs on Zepbound and counting.

I can still do my routines easily with no issues. My muscles look slightly smaller I think, but maybe that's the fat around them that's been diminished.

[mrtesthah]

There is nothing inherent in your description that would support your implied claim about facial aging.

[storus]

"Emerging research suggests GLP‑1 receptors are present on adipocytes and fibroblasts. Some animal studies indicate that GLP‑1 agonism may promote lipolysis in subcutaneous fat more aggressively than in visceral fat, leading to disproportionate loss of facial fat. It also may affect collagen synthesis or skin architecture, though human data are still evolving."