Three and Four Day Trips
As your adventures grow longer, you must pay increasing attention to exactly how much food you bring. The eyeball method leads to considerable errors when the trip is three or four days or more. Measuring out foods by volume can work if you know how many cups you typically eat for each individual item you want to bring. An easier way to bring exactly the right amount, however, is to weigh out your food on a postage scale. I know that five ounces of cereal, of any type, and one ounce of powdered milk is a satisfying breakfast for me. I have no idea how many cups of my six favorite cereals equal five ounces.
Foods differ greatly in their calorie content per ounce. As a general rule, carbohydrates and protein yield about 112 calories per ounce. Fats yield much more, about 250 calories per ounce. Since weight and bulk are a problem while backpacking, it's tempting to load up your pack with fats. Unfortunately, the best food for strenuous exercise consists of carbohydrates, which are relatively heavy for their caloric content. The best backpacking menu, therefore, is a compromise. Think of your food as firewood. Carbohydrates are the kindling, useful for getting the fire going fast and re-energizing a tired hiker quickly. Slow-burning fats and protein are like logs, good for fueling a steadily-burning fire and stoking the inner furnaces during a long, cold winter night. Don't worry too much about obtaining sufficient amounts of vitamins and minerals while backpacking. It's impossible to become seriously deficient in any particular nutrient during a week or two of hiking.
Most people need approximately two pounds of dry food per person per day. Cora, who's smaller than I am, needs a bit less than I do. Here's a prototype menu that Cora and I have used for four-day trips. The quantities listed are merely suggestions to get you in the right ballpark.