I use shiritaki/konjac noodles fairly often. They're made out of glucomannan which comes from a type of yam native to Asia, I think. It's nothing like what we call a yam (that's not actually a yam) in the US. Anyway, it's almost 100% fiber, so it is very low carb and low calorie. They give me a bit of constipation and gas though. I counteract it by using some coconut oil the next day.