Dehydrated foods are those that have been put into a dehydrator. Like the name implies, this process eliminates most of the moisture in a piece of food but it does change the structure of the object. Dehydrated foods are less expensive than freeze dried and can last for quite a long time as well. If you are going on a hiking or backpacking trip, taking dehydrated foods with you not only lightens your load but enables you to keep things in a backpack that would normally go bad quickly if not dehydrated. Dehydrating can be done at home. The machines cost only around $40 and make it easy for you to dry fruits, vegetables and meats, though almost anything you want can be dehydrated. Beef jerky, dried apple or banana slices are good to eat without any other action after dehydration, while food like dehydrated peas or potato flakes are not good unless you rehydrate them with hot water.
If you don't have a dehydrator, then sun drying is also an option. Some foods simply taste better if left to dry in the sun, such as tomatoes. Bring a bag of sun dried tomatoes with you on a camping trip and any pasta dish is instantly more gourmet. Raisins are another commonly sun dried food. Grapes left to the sun, can absorb a delicious flavor and are great in breads, cereals, granola mixes or plain. As long as they are kept in a sealed container, sun dried tomatoes and raisins can last for more than a month.
There are some foods that naturally last a long while without doing anything to them. Nuts are one of the main things, and are also a great source of protein. Raw almonds, peanuts, cashews, macadamia or Brazil nuts are great in granola mixes, hot cereal, in curries or plain. Nuts will keep for months in a sealed container or bag and can also be crushed to make nut butter. Dried legumes, such as lentils or kidney beans, are another good source of protein that can keep for months.