I'll hop in, though I'm likely to regret this. Note that I am not only replying to the parent comment here, but also addressing the general conversation descending.
The primary disconnect I see in this sort of disagreement about the importance of calories is what we count as "calories in" and what we count as "calories out". The calories listed on nutrition labels are determined by burning a sample of food in a bomb calorimeter. Since our body does not reach the efficiency of a bomb calorimeter, calories consumed through oral or intravenous ingestion will overstate the number of calories that are used by the human body calories in The nutrition label gives us an upper limit of what we can consider calories in, but does not, on its own, give us an actual value for this measure.
The other side of the disconnect is how we measure calories out. Some people consider only energy expenditure, or how many calories ingested are turned into energy for useful work in the body. Some may also consider those calories utilized for structural purposes. Protein does not necessarily get utilized for energy; in fact it is the least desirable energy source of the three macronutrients. Some may also consider the caloric value of excrement for measurement of calories out.
So calories in can be calories ingested, or calories "processed" (here loosely defined as anything that doesn't pass straight through to stool or urine). Calories out can be calories utilized for useful work, or anything that exits the body, as energy/heat or excrement.
Here alone we have enough for significant confusion among reasonable people depending on which definition they are using.
I hope this helps those involved in the conversation to clarify what they mean and consider that their conversation partner may be less of a moron than they assume.
Add to this that the only piece of this that we can accurately measure across populations is gross calories ingested, and there is a lot of room for reasonable people to disagree on a "healthy intake".
Please note: I am trying to be neutral in this comment, and to only help shed some light on where we find confusion in words. I am explicitly not making an argument for or against any specific interpretation of these words. If you choose to take issue with any inferred stake I hold, have fun. I am perfectly happy to consider discussion on the potential for confusion in the words we use when discussing the issue of caloric intake, though.
