Ok, do I really have to mention it yet again.

For the best concentration of nutrients and calories per unit mass or weight, that is shelf stable for months at a time, and probably the most economical product you can come up with, nothing out there beats good old pemmican. We're not talking about that processed beef jerky stuff you buy in little bags at the checkout lines, we're talking about authentic Hudson's bay trappers/mountain man/Lewis & Clark era survival rations. Easy to make, easy to store, highly versatile recipes, and pennies on the pound if you do it right. You will not find another food substance that has a higher concentration of calories per gram, or that can incorporate all sorts of custom nutritional models (to the limits of your imagination), that will hold up well under normal storage. Some of those "rat" bars may last longer on the shelf. But 6 months stock rollover seems prudent anyways. Besides, if you are as judicious about your processing and storage techniques as with those high priced commercial bars, pemmican will last just as long as they would. I can wrap a pemmican ball in aluminum foil and plastic and it will still be pallatable 3 months later.

We've posted recipes here before, and there are plenty of references all over the web, so I won't reproduce that all again here. It is well worth considering.

BTW, some pemmican recipes are also useful for accelerating fires.