For many people, diet and its composition matters a lot. As an example, some folks are lactose intolerant and will suffer digestive problems if they consume lactose (milk sugar). Other people have food allergies which can cause a severe, and potentially fatal, reaction if a food allergen is consumed. Others have sodium sensitive blood pressure and have to rigidly control sodium (table salt, msg and sodium nitrates and nitrites for example) in their diets. And, some, myself included, suffer from migrane. Many food items can serve as a migrane trigger and must be avoided.

So, if you can backpack on a steady diet of Cheeztos and Gatoraide count yourself lucky; diet planning need not be a large element of your trip planning. Others, however, are not so fortunate and need to know, exactly, the composition of every food item that goes in their pack.