Yes, the Asians tended to be slender because of rice as their staple. They come here, become Americanized and gain weight.
Their diets are much lower in fat. My daughter lived in Korea for a year. In the US she would never go near a McDonalds. Over there, periodically she’d get such a craving for fat she’d go to the only one in the city and get a mig mac and fries.
In one picture she was looking rather thin and I asked if she was eating enough. She said she was eating a lot. But she was having difficulty keeping her weight up on strictly Korean food. It took her a couple of months to get it back when she returned.
Interestingly, she said now that western [fast] food was coming to Korea, she could see the younger kids getting heavier.