GORP
As a staple of many hikers, GORP (good ol' raisins and peanuts) aka trail mix, is packed with energy! Pretty easy to eat on the go and not sticky or melty. A melty clump is not fun to deal with so choose ingredients wisely.
You can buy plenty of pre-made mixes, but the real fun is making your own. Put in just what you like. Nothing you don't.
If you're bougie: peanut m&ms, cashews, almonds, pistachios, honey roasted peanuts, dried cranberries and blueberries.
If you're not: peanuts, raisins and peanut m&ms
Whatever combination you use, it's one of the best ways to get calories in.
In long distance hiking, weight is everything. A lot of thru-hikers look for a calorie to ounce ratio of 100:1. A hundred calories or more for each ounce means it's pretty dense. Hopefully more fat and protein than sugar.
Buy ingredients in bulk and mix up a big batch. Vacuum seal in small amounts for the hiking season. A good way to not eat all of it. The worst feeling is when you eat too much on your first break, leaving little to none for the afternoon. And that's no fun!