Rice.
If you have fresh (or purified) water, an amazingly small amount of rice would suffice for 14 days. I've trekked the Cordillera Real for 12 days, and rice was the only reasonable option in terms of weight. A small set of spices - especially salt and pepper - dramatically improveimproves its taste.
If you don't want to eat the same food for 14 days, take other kinds of food (e.g. Pasta) and eat them the first few days, so that you'll carry a reasonable weight afterwards.