-- Last Updated: Aug-21-12 11:35 PM EST --
.....and one thing that you have to figure out, aside from storage space, is what will work with your digestive system. Also, are you making a trip on fresh water that you can filter and use or salt water where you may have to find, filter and carry water.
A very important consideration is that what you take on an extended trip is that you will probably not be eating what you normally eat on a daily basis and your body may take some time to think about it, especially if you are considering using energy and food replacement bars as your main food source.
Some of these ideas, including my own, may be "unsettling" and most wilderness experiences aren't equipped to gracefully accommodate the realities of diet change so be aware and conscious of local and environmental requirements.
I clearly recall using pages from Mark Twain's "Roughing It" for personal hygiene due to a toilet paper shortage.
Maybe too much information but at one time I was really broke but needed to compete in a national sporting competition. I scrounged around for sponsorship and, not being a high seed (for a good reason), I didn't secure the support I hoped for but did find a meal replacement bar company to provide me with a diet very similar to what you suggested.
I can tell you that the support provided the required calories but kind of slowed my digestion (if you get my meaning). Kinda made me uncomfortable. I would never go that route again unless faced with Armageddon.
On the other hand if your trip diet produces loose bowels you have this other, environmental and resource intensive, problem and you may want to carry lots of toilet paper and be prepared to squat over a hole below the next expected high tide line. Am I being too graphic?
From my standpoint I am thinking about 4 weeks and supplies. If you are paddling on fresh water and can filter what you spend your day on that is a bonus because you don't have to carry a supply. Salt water will complicate your storage question.
I think that 4 weeks produces a supply issue and that energy bars aren't a reliable food source for that period of time. Resupply or the expectation of defining the limits of considerable gastric experimentation within testing parameters should be tested now and established before being planned and implemented.