Dr. Phinney has a chart showing how this works. When we start giving our body very little carbohydrate and yet eat to satiation, the body soon regulates the appetite so that our food intake fuels about 60% of our metabolic needs, and excess body fat makes up the remaining 40%. But over time, as we shed fat, the percentages gradually change, while we still eat to satiety, so that if we stay on keto long enough, we have shed all our excess fat, and our food intake at that point satisfies 100% of our metabolic needs.
The caloric need may be a bit lower at this point than it was originally, given that we have less body mass to feed, but the key is not to eat to a caloric target, rather to let the body dictate food consumption by following our appetite. I’ve noticed, as well, that while appetite varies from day to day, my weight on keto has been stable since the initial loss.
Dr. Phinney said once, in an interview with the Dudes, that he and Prof. Volek generally have seen fat losses amounting to 20% of starting body weight. Richard responds that his fat loss was actually about 25%, so he is ahead of the game. I’m in the same situation, having lost about the same percentage. I wouldn’t object to losing another 30 kg or so, but there we are.
Not every underweight person dies of hunger on keto I am pretty sure! But even among fat ones, there are individual differences. Even full carnivore couldn’t do the trick that well to me but if I am very focused, I may have a tiny deficit. Or I can eat twice my needed calories, it’s very enjoyable and may automatically happens if I eat too fatty meat.