On day hikes I like to take things compact, portable, and non-refrigerated (but if you have a cooler you have some flexibility). My mix-and-match usually includes a selection from the following:
1. a meat, wedge/squeeze cheese, or nutella/peanut butter spread usually on crackers: sealed tuna packets (lemon pepper is good), ham or chicken salad cans, chunk chicken or tuna. Oh and my trail crackers are usually a little more substantial than saltines.
2. some sort of dense energy/protein/meal bar of your favorite Lara (my favorite) flavor
3. a fun food that you can maybe hold for later as an afternoon snack like corn nuts, meat stick, jerky, cookie pack, cheezit bags, fruit chews/gummies, etc.
4. besides water, I also have a gatorade mix to replace electrolytes. Or I start the hike/outing with one nalgene of gatorade and one or more nalgene of water. My point is to have some of both and not just all one or all the other.
Depends on where you find yourself at lunch time as to what you can do. If you think you'll be near a picnic ground near the vehicle, you can splurge a little on the menu above that some of the other folks have suggested. If you're at an overlook after a three hour hike up hill from the parking lot, you go with the compact, portable menu above. (That's usually where I find myself).
And of course, whatever you carry in (wrappers, cans, packets) gets carried out.
Bama Ed
PS - and after you get back home, Domino's delivers.