What food should I take?

I find it best to have your biggest meals at the beginning and end of the day. During the day you are going to want to be hiking and only want to stop for snacks and water breaks. If you eat a large lunch, you may have to go to the bathroom mid-hike, meaning you will have to stop, open your poop bag and find somewhere to squat. Also, the higher in elevation you go, the less of an appetite you have.

The night before the big hike, you should carbo-load. Eat some pasta, grilled chicken, etc.

The point is to consume a lot of calories in order to be ready to hike in the morning.

The morning of, you should have a light breakfast.

That means energy bars, oatmeal, dried fruit, bagel/bread, etc.

Breakfast:

Backpackers Pantry Granola with Banana's and Milk (Dehydrated Meal). Just add two cups of cold or hot water, stir it up and you're good to go. ($7.50)

Bananas
Apples
Bagel with Peanut Butter

While Hiking

Be sure to drink at least half a liter of water every hour if not more frequently.

Eat light foods every 1-2 hrs. That is fruits, nuts, energy bars, etc.

Aim for only one 10-15 min break every hour if not less often.

If you are hiking for a while and need to stop for lunch, take something that will not harden as you go higher in elevation. Aka no bread. Carry food that will give you energy to keep you going. Beef jerky is good, trail mix, energy bars, dried fruits, fresh fruits (mango, orange)

Mixed sports drinks are also a good idea to replenish electrolytes.

Oranges

Bananas 

Energy Bars

Apples

Nuts (Almonds, trail mix, etc)

Gatorade powder packs (add to water) Walmart has an 8 pack for around $8-10.

Tuna. ( Easy to eat and can be eaten with bread or chips or on its own)

Dinner

Mountain House Chicken Teriyaki with Rice (Dehydrated meal) $9.00 

Mashed Potatoes with Tuna (so re-moralizing after a long day of hiking)

If you can, have some more fruits so you are not just eating protein and dehydrated meals. You want some natural sugars. 

Drink lots of water (2-3 liters). You have been hiking all day and probably did not drink that much water. Your appetite and thirst go down the higher in elevation you get. Even though you may not feel that hungry or thirsty, drink anyway. Try to get your urine to be clear.