If you’re going backpacking for a little bit longer then you’re going to need to resupply unless you’re going to carry all the food for your trip. If you’re going to a particularly remote area then you might have to do that, pack every single food into your pack.
What that means is you’re going to have to have a pack that can carry heavier loads, but if you’re able to go into town, say go to the grocery store and buy more food, then you can carry less food and just resupply as you go along. The Appalachian Trail is a trail that you can do that Hike for a little bit, go into town, get some more food Here’s a couple of books put out by the Appalachian Trail Conservancy: A Thru-Hikers Planning Guide and A Thru-Hikers Companion These two books are nice in helping you plan your hike.
It talks a little bit about how to set up a post office drop, you can actually mail yourself some stuff, go to a local trail town’s post office and come in and say, “Hi, I’m so and so, I need to pick up a package for a thru-hiker,” and they’ll hand it to you. There’s a technique called bump boxes where, you can actually bump it to the next trail town, and then you don’t have to pay extra postage as long as you don’t open the box, you just say I want to bump this to the next place and give them the address. These books will list the addresses for all the post offices all along this particular trail. So, mailing yourself stuff is one way to resupply. Going in to a trail town is another way.
Downside to that is you’re going to have to take what is local so if you have specific dietary needs then you may want to use the mailing option. If you have any questions, give your local outfitter a howler.