Trust the food industry to turn the humble sandwich into a processed food. Uncrustables and other premade sandwich-like products are loaded with high-fructose corn syrup, trans fats, preservatives, and other additives but short on real food.
Better: It really isn't that difficult to make your own sandwiches, and you can even make your own "Uncrustables," sans nasty additives, that can be frozen ahead of time. Nut butters, chopped cooked meats, canned salmon, and grated cheese are all good freezable sandwich ingredients, according to the University of Nebraska Extension Service. Freeze your assembled sandwiches for about an hour before transferring them to a freezer-safe container, but add condiments and toppings like lettuce, tomatoes, onions, and pickles the day you eat it, since those can get limp and soggy in the freezer. To make a freezable PB&J, spread a little butter on the jelly side of your sandwich first to prevent the jam from soaking in and making your bread soggy.