When it comes to figuring out our optimal macronutrient intake, we get reports of a wide range of ideals. Most agree, limiting protein becomes important when the low-hanging-fruit of the controlled-carb diet has been harvested. Once you've cut all the carbohydrate-rich foods you're willing to forgo, reducing the amount of protein-foods adds that extra fillip necessary to get the fat burning again. More fat is added to the diet, and the scale starts measuring downward anew.
This seems to be pretty universally applicable in the LC community. The truism that low-carbing allows ad-libitum meat-eating is, like most of its logical kin, only true up to a point. Ideally, eating the appropriate meats will fill you up long before fat-burning is threatened, but in practice (especially as one approaches one's goal) it seems to be easy for some people to take in too much.
There seems to be one great big exception, though -- the closer to zero-carb you go, the more protein you NEED. Even though it's been documented that the body CAN make glucose out of fat, it appears to be easier for it to do so with protein.
Also, there are many beneficial effects of insulin that are stimulated in the ZC enthusiast by protein metabolism. Insulin is far from being "the enemy" to people who have trained their bodies to burn fat and ketones as the primary fuels! Going ultra-low-carb induces physiological insulin-resistance in muscle cells, particularly. To drive amino acids into cells for muscle-building (important in us old broads), we do need a bit of an insulin spike from time to time.
And it seems to work spontaneously. My husband, neighbors and local acquaintances see me too often to notice those body changes which happen over time, but when i was with some friends in the spring who hadn't seen me since last autumn, i was made aware of something: after a round of hugs, somebody said, "You're turning into quite a hardbody, aren't you?" I was surprised -- i have been very remiss when it comes to intentionally seeking a gain in strength. My goal is ENERGY ("vitality") gain as well as fat loss. It got me thinking....
Just as "the paleo diet becomes the fail-eo diet if you don't add enough fat," a ZC diet is not going to be healthy without sufficient protein. And ironically, it may be all about the insulin.