The Korean living in a very healthy lifestyle as compared to other countries. They do not really eat fried foods. If they are going to have one, it's not too oily. Their main meal always prepared with several types of vegetables besides meat. They usually have several types of raw fish for dinner together with some sushis and several types of vegetables (up to 7 types of veges).
You know it's hard to find an obese Korean. They are mostly thin people. Their buses seats are very small & narrow which is not a "big guy" friendly. They take quite about the same portion as other asians except that they don't take too much oil but having so much veges instead.
At the office, the koreans always brush their teeth including after having lunch. When I go to the toilet to take ablution for praying, I always bumped with Koreans brushing their teeth. What a healthy lifestyle they are having.