I've never had any problems putting together my food needs from a regular supermarket. And when I am packing for a week long backpack, I get pretty obsessional about weight and energy to weight ratios (target average is 2,200kj per 100g).
But the best place to get good, tasty, lightweight food for camping is an Asian Grocer. All sorts of goodies dried and packed ready to go
Of course with kayaking the room and weight is not such a premium so I often take some canned stuff as well.