"The 3,000 calorie thing has always been a little MRE myth. Actually the average MRE contains around 1,250 calories.

Never seen an MRE sealed in aluminum. I think C-rations from the Korean war were served in tins, but modern ones come in plastic pouches and thin cardboard boxes."

"I like MRE's.
But they're bulky, hard to come by before they’re close to expired, and not cheep.

When weight, volume or money are at issue, I like ER Bar's.
It's a 3 day supply of food (3600 calories)
In a 6"x6"x1" vacuum sealed aluminum pouch.
5 year shelf life (Same as a NEW MRE, and much better then surplus MRE’s)
You can get them on Amazon for less then 4 bucks. (A company called Quake Kare, makes Them.)
It tastes like Lemon Sugar cookies.
And doesn't require any cooking or mixing (saves your scarce water for drinking).

There are other similar products, but I haven't tasted those,. From the pictures some seem larger, and all cost more."