Total immersion in any culture will not be complete if you have not tasted that place's culinary delights.
The same holds true for Vietnamese cuisine, whose unique mix of Malay, French, and Indian influences make it a cuisine apart from the rest of the region.
In one word, most people describe Vietnamese cuisine as healthy, primarily because Vietnamese food doesn't contain much oil or spices. In Vietnam, rice and noodles are the staples.
Get more of Vietnamese cuisine in the article linked below.
Link: Vietnam travel guide - Vietnam Cuisine, Impressive And