Ashely Gilbertson, in The New York Times, recently wrote about the pre-packaged rations, comparing those from different countries. Excerpt
The menus and accompaniments are intended not just to nourish but also to remind the soldier of home. Some include branded comfort foods — Australians get a dark-brown spreadable yeast-paste treat called Vegemite, for example — while others get national staples like liverwurst (Germany), or lamb curry (Britain’s current culinary obsession).Read more. See also photos of the packs from a number of different countries. Some of the other packs look appealing, but I would stick with the Australian one. The others don't have Vegemite.
Some of the contents are practical. Italians get three disposable toothbrushes per day of combat. Americans get pound cake, which military folklore says reduces the need for toilet breaks.