On long distance bus trips in 3rd world countries, I absolutely cannot get sick. So while I'm riding, I try my best not to eat the local foods. I partake in the native cuisine only after I have arrived at my final destination. So on the bus, it's packaged foods from the States, bottled water, and beer.
Today, I went to Trader Joe's and stocked up for my Central America bus trip. I will be eating 16 Luna bars (8 flavors), two bags of beef jerky, and dried fruit (bananas and mangos).
But just in case, I'll also be bringing six rolls of toilet paper.