Here's the thing: It may be that 2400 calories would take the average 40 year old male and only have him continue the socially acceptable weight gain of a few lbs a year. Or maybe the average (already overweight) male would maintain his weight at 2400 calories.

But in any sane world, that's like the 90th percentile of calories required when consumed with a carb-heavy american diet and I'd argue almost no sedentary person requires that much. Just plugging in the basal metabolic rate numbers gets something well below that.