It's an intereting posit--this literal kind of "starvation" may be the natural and normal state of the human creature. Would make a fascinating study, but there's no profit in studying it for anyone. It simply means that your body is burning its fat stores for fuel. It doesn't mean you're walking around hungry. As a matter of fact, I can always tell when I'm throwing ketones because I don't get hungry.
Atkins' most difficult stage is when you reach your target weight. You're supposed to add back carbs very slowly and carefully until you know exactly how many you can consume without bad effects (weight gain is only the most obvious). One bad effect, IMO, is you get your appetite running overtime again with those increased carbs. Having lived so long without a lot of carbs--you start to like the advantages, and are leery and uncomfortable adding carbs, at least for me.
My brother lost about 75 pounds on Adkins about 15 years ago. He kept it off for about five years, but has gained it all back and more. He is now about 50 pounds higher than when he started.
I am firmly convinced it is. Early man did not store food. The only substantial real source of carbs during the winter was roots which have to be cooked. Cooking utensils per se (pots) have not been around that long. Man went into ketosis for months at a time! It is a natural state. That is why it feels good (all but the most extreme levels). Ketosis is a benficial state. It alleviates depression, makes you more alert, reduces hunger, gives you energy etc. All this with the side benefit of burning fat at an accelerated rate.
I have literally been in low level ketosis for months at a time.