Both yaki udon and lo mein are stir fried noodle dishes that use a soy sauce base. However, udon is a Japanese style noodle made with wheat and sometimes tapioca starch. It's also white in color. Lo mein noodles on the other hand, is used in Chinese cuisine, and is a type of egg noodles and is yellow in color. You can check out our shrimp lo mein recipe is you're interested.