You can't eat protein on a fast. Protein also increases blood sugar, and too much of it is detrimental in many ways and growth factors such as IGF-1 being just one.

You're moving the goal posts. We're not talking about a fast, we're talking about a very low carbohydrate diet. The paper I reference demonstrates that a carbohydrate restriction does not incur muscular catabolism when protein is a component of your low carbohydrate diet (which should primarily be fats to prevent excessive protein from kicking you out of ketosis).

Not really as low-carb diets are done mostly by people who do IF. Not all carbs are not evil! We've evolved to digest milk in adulthood and take advantage of slow carbs. The bad carbs are the refined ones - we haven't had much of these in the past. Low-carb diets are especially unsuited for women. If you look at people who lived healthy and long lives, they weren't gulping on coconut oil and refined MCT oils. Anyway, I don't think empty sugar calories are much different than empty fat calories. Carbs bring more nutrients than fats like coconut, for example. Nobody also cares on the microbiota effect of fat overload! Again, if you have epilepsy or schizophrenia, okay, no doubt, keto is great as therapy, but is it great for just anybody and does it lead to a long healthy life? There are no data to support such a statement! On the contrary, all anecdotal data points that moderation is the best strategy. Oh, wait - 6 meals a day is also a modern brainfart - people used to eat 1-2 times a day with no snacking! So, enough fad diets with no scientific proof behind them! The only thing that makes sense today is backed by research - maintain mitochondrial QC, cycle mito fusion with fission - all chronic diseases pretty much are caused by dysfunctional mitochondria, and I don't think keto supports that strategy well!

> as low-carb diets are done mostly by people who do IF

What? Maybe, but I think citation is needed there. The most widely popular keto diet, Atkins, doesn't say a thing about fasting - when you boil it down, and don't do any of the stupid carb-replacement recipe trickery that a lot of people do, Atkins equates to: take your normal meal with meat, starch, and vegetable, and stop making the starch, eat a little more vegetable if you want. Voila, there goes 500-1000 calories a day, more if you're eating starchy/sugary snacks. And you won't be hungry between meals. It's not rocket science.

I'd say what the parent refers to as intermittent fasting is just feeling less hungry...

Yes, the more frequently you eat, the faster your metabolism gets, and you get hungry faster. I'm not sure why people came up with the nonsense that faster metabolism is better as since when accelerating aging is desired? Well, muscle mass also ups basal metabolic rate, but that's a bit different mechanism.