I just got off a 7p to 7a hitch for 2 weeks.
My routine was to eat breakfast before I left my shift, and eat lunch/dinner when I came on shift.
So 2 meals a day for 2 weeks and according to my scale, I lost 8 pounds.
If I ate any midnight snacks I would have probably gained weight.
I do remember loving to eat midrats while at sea on the carrier though.