The weight comes down to a number of things, of which can include:
What you like to eat
How much you like to eat
What types of food you carry
And how fanatical you are in reaching the magical 125 cal/ounce (most people don't worry that much).
Food is the one item in my pack I just don't worry about weight wise - simply because as the days go by my pack gets lighter.
Worry first about planning a solid diet that has a wide range of what you need (protein, carbs, fiber, etc) that you like - not taking what you think you should eat but in reality can't stomach. Sure, there will be the person who can eat nuts and energy bars the entire week, but before committing to a new diet ask yourself what do you really like to eat?
I usually take a wide range of food - I like food, I like enjoying my meals. Some of it is pure fluff - low calories - but they are items that keep me going on long sections. That can be worth the weight right there.
Having said that I carry 1 to 1 1/2 lbs per day for me, my oldest son carries about 2 lbs or more. He eats a lot.