I'm about to turn 30, 4500 cals per day... Run to / walk from work (5 mi each way) plus walk to grocery store, 30-60 min lazy weights per day.
Ever since I 'bulked' in college, I never found myself able to go back to the tiny amounts that normal people seem to eat, except of course during my stint with galenikos diet plan.
In the end I think calorie math just simply doesn't work out... It's only good to track changes. Trying to add everything up using formulas, comparing yourself to other people, it never works out right.