It is probably good for you to learn basics of food and nutrition, and nutrition from a physiology point of view rather than a dietary nutritionists' point of view.

There are four Macronutrients in foods which give you calories. These macronutrients are, in alphabetical order, 1) Alcohol at roughly 7 Calories per gram, or about 190 Calories per ounce, 2) Carbohydrates at basically 4 Calories per gram or about 110 Calories per ounce, 3) Fat at basically 9 Calories per gram or about 250 Calories per ounce and 4) Protein (animal and vegetable) at about 4 Calories per gram or about 110 Calories per ounce. Some people give backpacking food planning guidelines as wanting to have 120 to 140 Calories per ounce so that the weight of the food needed to balance your high calorie burning will not weigh too much. The only way this will happen is to add fat.

We'll skip discussion of Alcohols.

Carbs and Proteins at 4 Cal/gm and Fat at 9 Cal/gm.

Carbs are cheap and processed carbs are convenient especially for backpackers. They come in packages and cardboard boxes and have a very long shelf/pack life. Carbs also digest to yield sugars such as blood glucose and frucose. The good thing is that carbs are convenient to carry such as pasta, instant mashed potatoes, instant rice as well as ordinary rice, dried fruits, dried beans, some breads or crackers and dried vegetables.

Fats are the greatest package for raw calories, and winter hikers are ordinarily especially encouraged to pack enough fats because the energy requirements of winter hiking and winter staying warm require calories.

Fats are the scum of the earth, according to vegetarian oriented nutritionists and are "tolerated" by more enlightened nutritionists and encouraged by a few more.

There are "good fats" and "bad fats" and "good calories" and "bad calories". It is modern to call "bad calories" those accompanying high glycemic index carbs. Everyone agrees, now, that omega 3 fats are "good" as well as monounsaturated things like olive oil and an enlightened few will look at the increased High Density Lipoprotein cholesterol and allow that saturated fats are good as well and the lack of small dense Low Density Lipoprotein is a bonus that outweighs the large fluffy LDL that comes from eating saturated fats.

Protein is needed to rebuild muscular and structural proteins that degrade with living and heavy exercise. Proteins are the only source of biologically useful Nitrogen in man, and that comes from the amino acids that combine to make up the proteins.

There are Essential Amino Acids, about 8 of them, that must be consumed because the liver cannot make them from other substances in the body. So, one can logically call proteins as essential.

There are essential fats as well. Your brain is about 1/2 fat and the cell walls of virtually every cell in your body is composed of fats, called the bilipid layer (lipid = fat). Without fats, you are just a blob of liquids and chemicals. If fats are so bad, how come nobody advocates a diet of less than 10% calories from fat, and even the major medical associations go along with 20% to 30% calories from fat. If it were really evil, wouldn't even less of it be advocated?

There are no essential carbohydrates. There are no essential carbohydrates. There is a food and diet report from the National Academy of Sciences that states that - Congress requires that this diet and nutrition report is updated every 3 years.

There is a claim that you need 130 grams of carbohydrates to generate the glucose that your brain runs upon, and there have long been claims that you only use 10% of your brain.

Surgeons have never been able to find the unused 90% of the brain, and physiologists have never been able to find brains wiped out by a week or two of fasting (no carbohydrates eaten). In fact, periodic fasting is long argued to be healthy. The 130 grams of carbs per day is a weak argument.

Your liver can convert both fat and protein to glucose, and there is an additional energy system called the ketogenic system which is based upon the burning of fat. Quite a few of your organs can run on it, as evidenced by "healthy fasting", and the pre-insulin treatment of diabetes which was a nearly carbohydrate free diet (ketogenic).

For backpacking, you will find that because of convenience of buying and carrying, your diet will be high in carbohydrates. It is very hard to create a low carbohydrate backpacking diet, unless you invest in equipment to do your own meat product processing. Oils are fairly easy to carry, but oils/fats in the form of cheese are much easier to eat in quantity. Buying hard cheeses in wax (NOT PROCESSED CHEESE)every week is a good option. Cheese is also the way the ancient Greeks used to preserve milk... they had no refrigerators, you know.

Peanut butter spread thickly is also great for your nutrition even if it has some fat.

Remember that neither fat nor protein cause much spike in your blood glucose, but carbohydrates do. You will find that the glycemic index is not defined/measured for either fat or protein, and there is a very good reason for that. When you find out WHY this is so, you have taken the first step to intelligently managing your backpacking diet.