Cold cuts with cheese and fruit are the common choice here. If you're planning lunch for the first or second day on the trail just about any kind of meat will do. Before you go you can freeze the meat, wrap it in newspaper and aluminum foil to insulate it and pack it in the center of your backpack, and it will easily keep for 24 hours or more.
For longer treks, select jerky or dry sausage, sometimes called "hunter's sausage," and choose hard cheese such as sharp cheddar, Gouda or Manchego. You may spend a little more, but the cheese should be fine for a week or more, so you won't have to fret about your lunch going bad before you get to it.
For sandwich bread, flat breads, tortillas and bagels all work great and are going to survive much better in a backpack than a regular loaf of white or wheat bread.
There are plenty of great options here. Pasta, particularly tortellini, works well as a one-pot meal, as do "Hamburger Helper" type meals, ramen, couscous and even instant mashed potatoes.
For protein, many supermarkets carry meats such as chicken, tuna and salmon in foil pouches, which is a great way to reduce weight.
Here's a trick with pasta sauce: Rather than carry a large jar or can, spread it on a greased cookie sheet at home and put it in the oven at 125 degrees. Use a magnet to prop open the oven door a half inch to allow the moisture to escape, and in approximately eight hours you'll have spaghetti sauce that looks like a fruit roll-up. Fold it up, place in a Ziploc back and you're all set.
Reconstitute the sauce in a pot or Nalgene bottle on the trail and you've got a great addition to your dinner with minimal weight. For variety, try pesto sauce as well.
Another great trick: The freezer-weight zip-top bags are great for cooking in. Put chicken from a pouch, instant mashed potato and a cheese stick into the bag, pour in some hot water and knead it with your hands for a couple minutes. You'll get to warm your hands if it's a chilly night, and get a hot, filling meal with the added bonus of the easiest KP (kitchen patrol) you'll ever do.
Snacks are an important part of backpacking food. You should snack throughout the day, rather than waiting for traditional meal times to eat and refuel constantly to keep your energy up, especially on a strenuous backpacking trip.
It's impossible to go wrong with nuts and dried fruit, which are available at most grocery stores or large warehouse chain stores. Or buy a dehydrator and you can try drying your own fruit.
And there are plenty of options for energy bars that pack high calorie counts into small packages. Sample as many as you can to find the ones that work for you.
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