Not sure after googling but the difference is hormonal measures versus statistics on dietary fiber intake for humans which are as old as the hills. The hormones from bellies are less of a challenge in rodents compared to humans than many other things…I would imagine. We are not talking about drug development either. In other words it is less DNA or cellular molecular related. Just a list of hormone reactions.
There are plenty of studies on increasing fiber intake.
The wild card might be we work all day a rodent does not. That changes our metabolic relation to time.