The noodles I buy at the big Asian store are less than 1g per serving which is about 1 ounce.
The ingredients are water, yam flour and hydrated lime (whatever that is)
They're called Shirataki (yam Noodle)

Thud suggested rinsing them and then microwaving for a couple of minutes before adding to a dish and that works really well.

It's sold in the refrigerated section of the store.