A good snack that my wife and I rely on both for gym days and hiking days are called “fat bombs”. Usually coconut oil with nuts/dried fruits/nut butters mixed in, and maybe some flax/hemp/chia for added fiber. We’ve also added 75%+ chocolate to them before, think bakers chocolate, to add a little boost of quick energy as well as flavor and texture. We keep them individually wrapped in plastic or parchment and deep freeze them before we hike. They thaw slow and can taste pretty good if you make them right.