For me, it was really the water that was problematic, as opposed to the food.

On my first visit, I was careful about the water I drank, but not very careful about other ingestion, and I got TD about halfway through the trip.

On the next visit, I was careful to keep my mouth closed while showering, and only use bottled water to clean my toothbrush, etc. Everyone else on the trip, eating the same food, got sick, but I didn't.

This is of course anecdata, but generally food, especially cooked food, is more likely to be safe.