I read some posts a while back about some japanese noodles called konyaku noodles. They are made form a type of yam (not sweet!) and they are very low carb.
I found some at a japanese grocery store and they're very yummy.
The noodles in restaurants are usually made of wheat or rice. They should know in the kitchen. Those two types of noodles are high carb.
I'm nor sure about 'bean' noodles though.
They won't harm you in the long run, but try the konyaku noodles if you want to make stuff at home.
Oh, by the way. They are very inexpensive...