Not sure how we're defining "big" .....
Yes, that is a key point that has not been addressed in this discussion.
Another question to ask regarding "Calorie Burn" is how many extra calories you burn by carrying a "big knife" (whatever that is) around all day long? Or to think of it another way, what other useful item(s) could I carry for the same weight penalty as that 6 or 8 or 10 or 12 inches of steel on my belt?
Everyone's situation and operating environment will be different. Therefore people are likely to come to different conclusions regarding what knives to carry in the field.
In my case, my default is to carry a modest folder in my pocket, and a smaller lightweight folder in my junk bag in my pack as a spare. Since I live/work/play in a region which can have a very severe climate, I generally opt to use that additional weight to carry an extra insulating layer in my pack (rather than steel on my belt). I'm not a gram-nazi, but especially as I get older I like to at least consider the weight penalty of everything I carry.
If I expect to be using a lot of wood (as opposed to a stove), and/or I'm traveling in a mode where weight is not such an issue (kayaking, or pulling a sled in winter), I would opt for a bow saw and/or a small hatchet.
About the only time I carry a fixed blade is when hunting. In that case it is a blade in the 5-6 inch range.