Thanks everyone for your responses. I'm going to dive into NCBI and see what it turns up. Thanks @skyraft, @Fiorella, @BillJay. I appreciate your thoughtful comments. This forum is awesome.
I suspect I'm having a language barrier actually. Where what Westman means is:
"Some fiber behaves like glucose in the body"
whereas what he said is
"Some fiber is absorbed as glucose"
Which is ambiguous, and I think I took him more literally than he intended.