Having been on a low carb diet for the better part of 2 years now, I question the conventional wisdom of needing carbs for energy. Fat is a much more dense source of energy. 
I have never experienced an issue with running out of energy, and it is just not a problem for the majority of the millions of people who are low carbing it.
 
Ditto.  I didn't want to be the first guy to mention it (because I usually am  :/) but I once read a summary of a study that indicated that even marathon runners and endurance athletes may be better off "fat loading" than "carb loading."  Still, for survival rations I will admit that fat could turn rancid and might be harder to store.  I like to keep things like Vienna Sausage, pouch tuna, Kipper snacks, Spam, nuts, mayo packets & jerky around.  They're all foods that last and things that fit my normal eating style.
I also find that eating 300 calories of a food fairly high in fat satisfies my hunger a lot better than a similar amount of most high carb foods.