I had the same problem. On loading days, I simply wasn't very hungry. It was hard to eat at all. Isn't that just awful? Finally you can eat whatever you want...and then you have no appetite! It's like a sick, cosmic joke.
Some people had luck getting their calories in by drinking them. (i.e. milkshakes, etc.) I ate steak and fatty meats. I have to stay away from sugar anyway because it gives me cravings for more and more sugar...I think I ate a baked potato with a LOT of butter, too. I didn't eat until I felt sick...but I felt VERY full after eating and ate to capacity.