as one goes deeper into a trip, the food poundage needs to ramp up. it's not miles that matter, unless they are special identical designated trail miles that are somehow are all the same.
you push 10-12 hrs hard, you need food.
longer weeks pushing will = more needs.
given a stable situation of walking and eating (no towns), eventually it will level out at about 3# a day.
one can save all sorts of weight the first several weeks though. and that's all fun and a light pack. but eventually you will run out of games to play, and have to eat real lots of food.
the better condition one is in, the faster this will happen.
one can focus on mpd, but you're going to find out once you leave the grid, that it's a dead end path which lacks flexibility to deal with the variables of wilderness travel.
food, it's a good thing.