If you listen to Dr. Greger's argument in the video between 2:05 and 2:11, he is arguing that the waste excretion is rate limited and therefore increasing bulk flow
through higher fiber intake will help this process along.
However, the effects of dietary
fiber on glycemic control were considered inconsequential.1 Furthermore, the expert panel of the ADA considered it difficult to achieve a
high dietary
intake of soluble
fiber without consuming foods or supplements fortified with
fiber.1 We therefore designed the present study to determine the effects on glycemic control and plasma lipid concentrations of increasing the
intake of dietary
fiber in patients with type 2 diabetes exclusively
through the consumption of foods not fortified with
fiber (unfortified foods) to a level beyond that recommended by the ADA.