Normally I'd say a high school age person should be familiar with a bunch of typical sweets from their home country, maybe even some from foreign countries these days, but this is Akira we are talking about. The only thing in life he's interested in is moving and transferring schools. So, he would only be familiar with quick meals at rest areas, where his family would stop for a break when they move from one town to another. Maybe he has tasted a doughnut at such an establishment, but that's it.