1400 kcal is simply impossible for me, starvation for many of us… But perfect for some people, sure.
It’s very stupid when people just say “a woman must eat X calories to lose weight” and other such rot, I so hate that. Some woman clearly could lose fat eating 3000 kcal (and high-carb), we aren’t all the same! But 1400 kcal is very little for many women (and most men). I couldn’t pull that off, no matter what, not even my top satiating items and eating once a day (not like I often can do that but that minimizes my energy intake).
Yeah, some people don’t think our health and well-being matters at all when losing weight… I never understood that. But even the CICO forum I frequent knows about not going too low, it’s widely known… I can’t imagine not losing fat when eating too little, it makes zero sense to me - unless someone is in some very strange place, with some insanely sparing body (that most of us can’t have) and just enough energy intake to “maintain” (but some not fat tissue breaking down happens too and we don’t want that)…? Slight starvation more easily does that but that requires some “abnormal” behavior too. A small deficit shouldn’t harm my metabolism and never did as far as I can tell. Some people aren’t this lucky, I know that. But using only 600 kcal for everything? How a human body can do THAT? Mine never could and especially not without becoming skin and bones first and skipping all activity… We are big warm-blooded animals. There are tricks but they have a limit… But less so in some cases. I heard multiple stories from very trustworthy people so I believe they are like that but it’s still amazing to me.
600 is insane, 0 is better at that point… Not too often, of course.
But deficit is needed unless some has a magical body that throws away precious energy reserves. Quite some of us in this forum can’t just eat very low-carb (even carnivore) and expect fat-loss, it just doesn’t happen. Most (all?) of the others who lose automatically eat in a calorie deficit on keto, I am quite sure.
What keto does to our energy need may be another interesting question (and I know nothing about it), it does nothing to mine, sadly. I so could use just a tiny help but nope. Oh well, it helps in another ways (Not ketosis itself but being low-carb enough.)
But it’s complicated. We can’t just eat X calories and expect anything good, we need to do what works for our individual body (and mind. no matter what is ideal for my body if no way I will ever do that for long because of mental reasons).