A trick I learned many years ago when I was in the scouts. I would take a steak or 2, maybe some hamburger or some stewing beef. I also did the same with bacon or a slice of ham. The meat was frozen in the freezer. Then just before leaving it would be wrapped in foil and a couple of sheets of newspaper. These packets would then be wrapped in spare cloths and stuffed into the middle of the pack. I would also crack some eggs into an ice cube tray and freeze. Then pop the desired number of these egg cubes into a baggie. These would be wrapped the same way as the meat. The foil and the newspaper are for insulation and to keep the clothing clean and dry.
I've heard that Egg Beaters can be frozen and carried in a similar manner. Might be nice because of less chance of a leak. I usually buy a package of Egg Beaters that has 3 small cups, each cup containing the equivalent of 2 eggs. The cup has a foil peel back lid. These might be real nice.
I've got a 5 day trip this summer to climb the tallest peak in Utah and I think I may take fresh food for the first couple days! Omlet for breakfast on day one and steak for dinner that night.