On another topic, old family recipes were delved into to find food suitable for a person who is very ill. One idea was Lemon Sago, a bland non-fibrous yet tasty substance, perfect really, yet the appeal was limited! Cream goes well over the lemon.
Tapioca and sago seem to be the same thing although the final texture had larger fuller 'blobs' than I recall. All guess work, as a number of recipes are found all with variations in the amounts.
As purchased, the tiny 'grains' of sago are made from processing the plant material to obtain a starchy substance, I suppose. So, the grains do not grow on trees and Wikipedia could tell the story.
Boil 2 cups water. Add three quarter cup of sago and stir till boiling and simmer 15-20 minutes. Add half cup lemon juice and grated rind and a tablespoon of honey or golden syrup. Cook another 2 minutes.
So, tapioca is an ingredient in those truly amazing Asian drinks, for example those based on green tea and found at cafe style shops in the Sydney suburbs. And tapioca does have fibre afterall.