If the ratio of fat to protein is high, and exogenous carbohydrates is relatively low in contrast, insulin levels should be closer to baseline (than a standard diet), as well as blood glucose, thereby keeping the Randle cycle minimized and so consumed energy gets used more by an on-demand basis or it gets dumped (literally). Part of the reason we poop is because, if our bodies literally used all of the mass we consume, we would either get too large in short order or spontaneously combust.
I don't think someone here is lying. There may be some level of exaggeration, as in my experience a lot of cheese (particularly hard cheeses) can lead to extremely painful stools, but calories really aren't as meaningful as one might assume, especially when switching from a diet that directly supplies carbohydrate and one that doesn't.
The human body needs a certain amount of glucose in the blood, but it can't get that from fats (at least as far as I am aware). It can obtain it from protein through a process called gluconeogenesis, but that's a relatively expensive process that requires more ATP than what ultimately results from it. The human body also treats that process in a more demand-driven manner than one where exogenous carbohydrates are consumed. This isn't an absolute, but it's generally less supply-driven. If protein can't be used for glucose or building tissue, it's more likely to become waste eventually.
I don't think someone here is lying. There may be some level of exaggeration, as in my experience a lot of cheese (particularly hard cheeses) can lead to extremely painful stools, but calories really aren't as meaningful as one might assume, especially when switching from a diet that directly supplies carbohydrate and one that doesn't.
The human body needs a certain amount of glucose in the blood, but it can't get that from fats (at least as far as I am aware). It can obtain it from protein through a process called gluconeogenesis, but that's a relatively expensive process that requires more ATP than what ultimately results from it. The human body also treats that process in a more demand-driven manner than one where exogenous carbohydrates are consumed. This isn't an absolute, but it's generally less supply-driven. If protein can't be used for glucose or building tissue, it's more likely to become waste eventually.
See "rabbit starvation":
https://hekint.org/2022/01/26/rabbit-starvation-protein-pois...