You guys need to eat more red meat, rich fatty seafood, dark green vegetables, fruits and salads. If you’re going to eat just bananas and milk at least try to take a soft-capsule multivitamin.
Make a rich soup in a huge vat and put it in your fridge. You can eat that for a week. Also, frozen vegetables. You are right, canned food should only be eaten very rarely.
Eggs. Are easy to make, and you can even make them in the microwave. No, do not try to microwave a whole egg. Crack it in a bowl, poke a hole in the yolk and cover it with Saran Wrap. 30 seconds. Steak sauce, ketchup and mayonnaise. Have some boiled spinach and that’s quite healthy already.