[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]

Your body doesn't enter starvation mode until you are in the 4-6% body fat range no matter what your diet is.

I linked 3 reviews/analysis of a large group of studies.

Your study also doesn't argue what you think it argues.

> A total of 33 studies were analyzed, revealing no significant differences between the KD and other diets in muscle mass

But fundamentally it is not a meta-analysis of people on weight-loss diets, it is a meta-analysis of people on keto. Look at the included studies - nearly half of them were on athletes. They weren't tried to lose weight - they were just eating keto. No one is saying that maintaining on keto is going to cause muscle loss.

Your confidence is the problem here - you're throwing around a bunch of words you don't understand and linking studies you didn't read.