I think you may be confusing Pemmican with hardtack. Hardtack is cracker type food made of flour, water and salt. It is generally so hard that you need to either gnaw on it or dip it in liquid to soften it enough to eat.
Pemmican is basically dried meat mixed with fat, and it actually has a lot of fat, generally about half as much fat as meat by weight, which means that more of the calories actually come from fat. Generally carbohydrates, such a dried fruit would also be added.
Fat is very important to human life. There have been stories of people starving to death when the only food available was lean mean (ie Rabbit Starvation). Most societies that are based in very cold climates have fat as a very important part of their diet.