Other alternative is to make your own granola if fat is a concern. I don't know any recipes for low-fat ones but they're allegedly out there. Dried dates are also an excellent source of nutrition and fibre (if not sugar).

You might want to consider good-quality meat jerky and pemmican as it's dehydrated and light (hard to find though) and I think most of the fat has been taken out.

The sausages earlier mentioned are the winter sausages often found in Europe. They have a waxy or powdery white coating, are very firm (dessicated), bit withered at the ends and have a string to hang them up. Unfortunately, fat-wise, they contain quite a bit of fat as that acts as a preservative.

I'd avoid any liquidy stuff (including viscous stuff like PB - it'll find a way to escape).