I am a bit conflicted. According to the comments, one should do very low carb diet to adapt to Ketones as energy. For example, fasting would not be enough for this purpose.
But that implies the need for a ketogenic diet.
Very low carb diets are difficult to do, at least if you are not very rich: Most of them require a lot of meat.
Now, that differs by country. These diets are probably easiest to do in the USA with its huge industrial meat industry.
In other countries, like here in Europe, you'd probably need to be a millionaire to buy that much meat in the first place. I don't know anyone doing this successfully.
But in any case: is it ethical? I doubt that this would be sustainable for everyone. If everyone would eat mostly red meat, we'd probably roast our planet pretty quickly. I don't think free range farming would support 7 billion carnivores, nor would the fish in the sea.
I realize the people doing Low Carb are not necessarily the same who care about sustainability. But if there is such a benefit to Ketogenic diets - for all our sakes - we should think about what happens if everyone wants to do it.
Of course there are options. There are low carb Vegans (e.g. https://www.reddit.com/r/veganketo/), but boy is it a chore to do. Also, I doubt this can be done with anything resembling local and unprocessed products.
Furthermore, a lot of vegan protein products are high in soy. Which is fine really for any amount you'd normally consume. But if you are serious about low carb, you might eat so much that we get into that "questionable" range in terms of recent research.
Perhaps carbs need not be too low. Yeah we can eat a lot of veggies, probably. But it'll be a challenge, I think.
Or not?
Say, you eat meat once a week. How do you do a ketogenic diet without losing your mind in planning etc?