No, not all naans are the same. Pakistani and Indian naan are different, and these are different from Afghanistan. Turkish and Lebanese flatbread appear usually very white and round, whereas Pakistani and Indian rogni nan are thicker (1/2"+ and light brown) and round.
Afghan naan tends to be elongated and thin, usually brown in color from a heavier wheat flour. All are fairly healthy, as they are typically made from a natural yeast, with the dough started continually used over and over again - nan, no matter which country it is from in the Middle East, often has a bit of a sourbread flavor.
Why?
Poor people don't have the luxury of having store-bought yeast - they have to start with natural processes and keep their starter going the "old fashioned" way. I'm working on a homemade pita bread recipe - I'll post it as soon as I have time to iron out the kinks! I cannot wait to try it out with my homemade hummus recipe I posted today!