Spirit, I believe Dr. A recommends eating about every 3 hours in the book. You DEFINITELY need to eat at least as often as you are truly hungry, and if you want to stave off the blood sugar drops that cause us to overeat in our rush to get something in our bellies, I'd eat every 3. Keep it healthy, but there's no reason you have to stick to salads. I'd think some 3 bean salad, a leftover (small) serving of Taco bake on cabbage, etc. would be filling and healthy.
If I were you, I'd make sure I'm calculating my calories based on 24 hour periods, rather than on how long
my "day" has been. Then your calories shouldn't be high. Besides, you're up and moving during those hours, not sleeping, so it's different.
I'm a night owl and when I stay up until 5 or so in the morning, I usually need to eat a snack around 2 or so. I count it as part of the following day.
Hope that helps!