@thor

> i'm aware of ketones as an alternative energy source to glucose, but wasn't aware they could also be converted to fat.

Not only is it possible but the pathway happens directly int he mitochondria. Essentially the keytone interacts with ATP to produce fatty acids and the process goes both ways. When we burn fat it is **always** through more or less the same pathway as burning protein. That is when we burn fat we convert it to keytones, not sugar.

Oddly enough it is sugar that has a one way relationship, while it can be converted into fat when we break down fat it wont convert back to sugar but instead will be in its ketone form (methyl-CoA if you want to get specific if memory serves)

> lab studies in animals suggest that we tend to consume less food if it's rich in protein though.

This is absolutely correct, but it isnt related to inefficiencies or an inability to get fat off of it. ITs due what i explained earlier, since protein and fat are both non-sugar energy sources they dont result in insulin. Insulin tells your body "turn all the sugar in my blood to fat and make me feel hungry again", so naturally the more sugar you get the more you will eat. Protein also has a synergistic effect with carbs, it slows downt he absorption of protein causing your sugar spike to be flattened over a longer period. Since insulin is triggered based on max blood sugar if this spike is below a certain level it wont triggewr an insulin event and will mitigate hunger as well even through its effect on the carbs.

> most foods have a rather modest protein content. it makes sense to focus a bit more on it than the others. that's also what i was instructed to do after my weight loss surgery.

Focusing your diet on fats and protein while minimizing carbs is an effective and proven approach to dieting. I am not disagreeing with your conclusions about protein being healthier, i am just disagreeing with the logic you used to get there to try to help you to better understand the process behind it all.

> my small intestine is shorter than normal because a significant part of it was removed as part of weight loss surgery. my ability to digest carbohydrates, particularly sugar, has been reduced considerably.

I am not a doctor so i wont comment on the pros and cons here or anything. But yea that adds up and makes sense along with many of the gastrosurgeries that may be used. If its effective for you or not I cant say but it works for many.

> of the two remaining macronutrients, protein is the less calorie dense one.

Calorie density is a poor way to view the issue IMO. Fiber is the least calorie dense, but you will never feel satisfied, and if you dont get enough fat protein wont m=satisfy you either. Also too high a protein count is very bad for your liver. If you truely eat all protein and little fat your body wont be able to process it into ketones or fat fast enough. The result is that a small amount will start to pass through yoru kidneys and it is **extremely** bad for your kidneys once you get to a certain extreme.

Long story short a low carb diet should have moderate protein and no more and largely be focused on fat for calories. Ideally healthy fats like omegas.