Almost every time I travel in Africa I bump into people cycling from London to Cape Town (or vice versa). Their needs include cooking food and purifying water, plus huge water carrying ability, a medical kit, maps, paperwork and so on. They obviously have to carry some food, as well as being able to repair any mechanical catastrophe on the bike at least well enough to get to the next town (which could be 5 days ride away).
So, what I am getting at is that we need a little more information before you can get any sort of sensible answer.
Mike