I'm a huge fan of MRE's - and generally keep 4-5 cases in stock at the house.
@mad dog 's meal was a 2014 produced Menu 8. The last year of the powdered dairy milk shake
at 1200 calories, they are very efficient, ridiculously shelf stable for 5+ years, and convenient - if not bland. Canadian IMP's put MRE's to shame - and the various NATO country 24 hour ration packs are a delight - to see what's possible. (Pork liver patte in the French 24 hour pack).
The mac-daddy deluxe of US rations are the 24 hour "First Strike" ration packs - a full 4,000 calories for three meals of food you can eat on the run. These are hard - but not impossible to find.