With more than 1.5 billion people and a median age under 20, Africa with a GDP of $2.8 trillion is fast becoming one of the most important growth markets for the global fast-food industry.

In total, I clocked 204 miles on my Prius in pursuit of an excellent burger. This is not something meant to elicit praise, surprise, disgust or a call from my gastroenterologist. It’s what happens ...