Again, it comes down to breaking down the calories into macros and not just calories as a whole. It's also depends on what the activity is. In this case (fat) I would adjust the macros high protein, lower carbs (not zero) and higher fat. If it were an athlete trying to lose weight, Higher carbs, med protein, lower in fat. Macros are always adjusted with activity. I would never go low carb, low fat except in the case of bodybuilding. Those are just some examples.
What foods are you going to choose? Absorption? Digestion, nutrient dense? What's the timing going to be? What micros will cancel out one another?
I agree w this esp your take on the 'nutritional' function of the cal vs the activity level/ demands of the athlete, something I've been paying very close attention to as of late.
but it kind of goes to reinforce my stance - you don't need high cals to get sufficient nutrients based on your activity level. as strictly a sedentary bber (aren't they all) you can pack a lot of density in 1000-1200 cal and in the case of bigger guys like myself up to 1500 some days which this type of diet is geared towards given the forum we are on. bbers imo grossly overeat when either dieting or gaining. most don't have the physical demands to require the cals they are taking in. I've proven I myself and others eliminating cals gives faster more efficient results w the same ability to perform 'work'.
if we were on a different forum I'd have markedly different ideas on cal intakes, esp given my own activity level which has a very high caloric demand at times.
I'm still trying to figure that ideal cal imput out for myself. it took me 20 years to figure out the bbing end of it. I don't have 20 years to figure out my athletic demands end of it.

I'm experimenting a ketogenic diet and prolonged HIT cardio and training. I went hypo today after 3 days w no carbs and very moderate activity. I was hoping keto could offer a virtually limitless fuel source (body fat combined w how fast some fats are metabolized for fuel) when I'm pushing myself cardio wise but it seems that keto and HIT cardio might not work out. it's frustrating- spend 3 days getting into keto then go hypo w out even pushing the throttle, so I need to eat carbs kick myself out ahd go thru the lag again and hope I don't go hypo until I'm 100% functioning keto?
I know conventional wisdom says 'carbs' for endurance athletes. but I'm not big on conventionality as you can tell from my ideologies. I just want to see if it's 100% necessary and the most efficient fuel source but fuck if I can get in and stay in that problematic in and of itself.