Planning your meals doesn't have to be as fussy as it sounds: if you want to eat peanut butter sandwiches and baked beans for two days, that's fine. But if you forget the can opener, half your meal plan is shot, so write it down.
If it helps, jot down menus for each meal. Then think about what you'll need to prepare or serve each of these delights, including ingredients and utensils. If you're bringing perishable food or items you'd like to keep cold, you'll need a cooler and ice. Here are some food and drink suggestions:
Some good, easy breakfast foods are bread (or bagels or tortillas), jam, fruit (fresh or dried), granola, instant hot cereal, and tea, coffee, or cocoa (don't forget to pack sugar, creamer, spoons, cups, and a coffee pot). If you have a cooler, try eggs, pancakes, and bacon (remember to bring a skillet and spatula, and butter and maple syrup).
For lunch, portable, no-fuss food is ideal: bread, lunch meat, cheese, carrots and celery, fruit, and peanut butter and jelly. Fruit, nuts, crackers, trail mix, energy bars, and chocolate are all terrific snacks.
For dinner, canned beans and vegetables, soups and stews, pasta and instant rice, garlic bread, hot dogs and hamburgers, burritos, baked potatoes, grilled fish or chicken, instant pudding, and s'mores are all simple and tasty. Remember to bring the utensils, pots, plates, and any condiments you'll need.
If you like, pack other beverages, but first make sure you'll have enough drinking water, or the means to make water drinkable. Count on about a gallon per person per day.
Backpackers face special food challenges: they need to limit the weight of their packs and they need a lot of energy. Freeze-dried foods are effective, and so are basic fuel foods like peanut butter, cheese, nuts, and jerky. Beyond the basics, many backpackers manage to eat very well in the backcountry. It just takes a little practice.