Just to add my own advice to that of those who have already responded...I cannot stress enough the importance of only carrying the bare minimum that you need to camp with, and only using the lightest camping kit available....if you can afford it.
I don't think carrying two weeks worth of food with you is a very good idea, firstly because just a weeks worth of food could easily weigh a couple of Kg's (4.4 lbs), and that is a lot of weight to carry when it comes to ultralight wild camping. So carefully consider the items of food you are prepared to carry.
Unless you are planning on staying in one spot for the entire two weeks (and risk being discovered by a disgruntled landowner!), it is very likely that you will come across somewhere to buy food at some point along the way, between various camping spots, and this will reduce the need to carry so much food with you...Of course, if you ration your food you can make it last much longer, so consider this too.
You can also reduce the need to carry so much food by learning which free wild foods are available in the area you are planning on camping in, and utilising them as wayside snacks to stave off feelings of hunger...This could easily make your weeks worth of food last more than two weeks. I don't mean hunting wild animals though...In the UK there are a lot of free edible plants, fruits and leaves and berries about in the countryside, depending on the season, if you know where to look and how to identify them.
Also, ditching heavy staple food items like Sugar, for much lighter and much more compact sweetener tablets, when you have a brew is a good way to reduce the weight and size of your food bag. By reducing the size and weight of all the camping items you carry, the smaller the backpack you will need...And this in turn reduces the trail weight of your backpack.
I get away with using a 100% waterproof, 35 litre backpack, that only weighs about 760g (A Mountain Hardware Scrambler RT35 Outdry). It has two concealed vertical daisy chains on the back which allows me to increase my pack capacity by attaching smaller additional packs externally to the back of it, as required, via some custom 10 or 15mm wide webbing straps, so you don't necessarily need to use a huge, heavy backpack that can carry everything internally.