The noodles, which come in lots of familiar shapes such as spaghetti, angel hair, and fettuccini, are made of water and fiber from a plant called konjac yam instead of from wheat flour. They are naturally calorie- and carb-free, because the fiber they contain is not absorbed by the body. Tofu shirataki, a type made from soybeans and yam flour has about 20 calories and three grams of carbohydrates per serving.
