An interesting article, which begs another question. Are the intestines of Japanese bigger compared to those of neighbouring Asians - the Chinese and the Koreans (from whom they apparently descended despite a reluctance to accept this fact) ? This should answer the question of whether it's the genetics at play or the diet itself.

Remember the American doctor mentioned Asian women and not Japanese. Statistically speaking there is a higher chance that the woman with long intestines happens to be Chinese. His comment also brings up another interesting question as to whether the lengths of male and female intestine are different. Why did he mention women specifically?