I think it's also easy to undereat if you exercise a lot --- IF you're counting calories, trying to run even a moderate deficit (not extreme), yet forgetting to account for the calories burned by all that exercising.

I wonder if that's what Steely Dan was experiencing. I can't tell if his 1400 cal/day is "gross" or "net" calories, but his post reminded me of other guys I know who also tried to eat that little while exercising heavily every day and ended up feeling like crap.

For example, I did some cardio this afternoon that my Garmin claims burned just under 400 calories. If I tried eating just 1400 calories, I've got around 1000 left to do everything I need to do during the other 23 hours of my day -- and that's really not a whole lot when you think about it.

When I was using LoseIt! religiously, it guesstimated that my daily calorie budget would be 1800-1900 calories. If I exercised, I could afford to eat more; if I didn't exercise, I had to eat less. If I had a big workout or a long, fast bike ride (or shoveled snow for six hours ), I ate nearly 3000 calories.

Once I made it a habit, and after six months of doing it every single day, I didn't feel crappy or hungry, I felt... well, I felt great. 30 pounds lighter, more energetic, and just plain happier.