Hang in there GOB!
I am sorta in the same boat, 5'7" 210lbs, and I don't eat that much at all. Yes I drink more soda than I should, and since I am a truck driver, well...it isn't the most active of lifestyles.
I am interested in what you mentioned about not eating enough.
It makes good horse sense, do you have any additional info in that?
I remember when I was on active duty, I always had problems with weight. I did always pass the tape or calipers test, but when they had me go on diets several times, I actually gained weight, not lost it. I just never fit their "height/weight" tables.
Keep with it GOB!