Warning: End of Series and Movie Spoilers. You know the drill.
I'm willing to bet it tastes like crap. :P
Here is a photo of a FMA movie banner infront of a Lawson. Same source.
You can also buy other FMA (Loopi Goods) stuff at Lawson:
http://www.at-lawson.com/ItemView.cfm?layoutgroupid=7800&shopid=13&parentitemgroupid=6223