Nuts and Seeds
Trail mix is appropriately named, because its bedrock ingredients consist of calorie-dense food--nuts. Sunflower seeds, pumpkin seeds, cashews, peanuts, almonds, macadamia nuts and virtually all other forms of seeds and nuts routinely pack more than 150 calories per ounce, making them one of the most calorie-dense sources of food available. Furthermore, nuts are already preserved, and as long as the nuts are kept dry they stay that way. Nuts are also a good source of other nutrients, depending on the nut. Macadamias and pecans provide B1 vitamins, while almonds are rich in vitamin E and many minerals. While the exact nut or seed varies, these two sources of food appear on virtually every sample list of backpacking food out there.
Dried Fruits
Along with nuts are dried fruits. Mix the two together and the result is trail mix. Like nuts, virtually no published backpacking foods list leaves out dried fruits. Ultralightbackpacker.com and the the-ultralight-site.com both like raisins and dried apricots, while adventurealan.com suggests dried apples, prunes and mango, but the consensus is that dried fruits are a calorie-dense source of nutrition, especially vitamin A.
Jerky
Most sources agree that jerky is a good source of preserved protein, but disagree on the source for the jerky. Adventurealan.com's sample backpacking menus insist upon vegan jerky and soy jerky, while the-ultralight-site.com goes straight for old fashioned beef jerky. Ironically, the artificial soy and vegan jerky is probably preferable, because it is more calorie dense and packs more than 100 calories per ounce, compared with beef jerky's lighter 70 calories per ounce. Still, if a backpacker wants the taste of real meat, then real beef or turkey jerky is a sound backpacking food.
Peanut Butter
Peanut butter also appears on many backpacking food lists, which is no surprise since it packs 160 calories per ounce and takes years to spoil if properly stored. It is a classic camping spread for granola bars, crackers, hardtack and tortillas and is just as good eaten straight from the jar. However, peanut butter is also packed with minerals. One serving of peanut butter has 11 percent of the recommended daily allowance (RDA) of calcium, making it a solid substitute for easily spoiled dairy products on the trail. That same serving packs a whopping one quarter of the RDA of iron.