One of my favorite standbys Idahoan Instant mashed potatoes, any flavor and a packet (not canned) of tuna or chicken. Throw the tuna or chicken in a little more than 2cups of water, 2 packs if it's been or will be a hard day. Let it boil a few minutes with whatever spice you choose, I always add salt, lotta pepper. Stir in the spuds and chow down. It's worked wonders getting me back in top gear after a long cold wet hike to make camp. I sometimes add Parmesan, bacos, pine nuts.
No matter what I pack I always take some hot sauce and a variety of spices. My appetite really falls off in the woods, even when going uphill all day, not sure why, can't handle bland. I also pack a lot of drink mixes, Propel, Gatorade. Instant coco to mix with instant coffee====jet fuel..