Lot’s of good suggestions here. Four days isn’t really that long. You could not eat a thing and probably still survive. I don’t recommend that, just to put things in perspective.
I’ve done Backpacker’s Pantry before, and it is fine, but you have to pack out the trash. Remnant trash kind of eats away at my wilderness experience so I prefer to avoid packaging that can’t be reused. REI has ratings on their BP selection that was real helpful to me.
I always do oatmeal for breakfast, and bring raisins to mix into it. On a longer trip, I’ll bring sugar just to keep things interesting. Sugar can be dual purpose (put it on peanut butter and bread to make a sandwich or in tomato sauce to cut the tartness). It’s fast, healthy, lightweight, and filling.
For lunch, I do sandwiches (bread and peanut butter and sugar), citrus fruits (citrus I always crave after a couple of days so it is worth the weight for me), dried fruits. I mix dried fruit into oatmeal, too, to mix things up, and dried coconut is nice in oatmeal as well as in rice (creamy).
For dinner, I do pasta, couscous, risotto, rice, beans, and bring spices and tomato sauce. Spices are pretty light, and pack tons of flavor.
Some dried meats will last a long time without refrigeration.
Is there anything growing where you’ll be going that you could scavenge? If so, you could plan on collecting some food along the way.
I wouldn’t want to lug gatorade in a pack. It isn’t multi-functional, and only tastes good to me under extreme physical fatigue. Will you be hiking near water? If so, just pack a 1L bottle and plan to refill (boil or filter). Water is the heaviest thing I pack so I don’t want to carry a lot of it at any given time.
MREs are okay, but again lots of packaging.
Pack as light as possible. The lighter your pack, the more enjoyable the trip.