SAMA HOOLE: The fiber recommendation went from 0g to 25-35g daily in the 1970s. Not because new evidence emerged. Because the grain industry needed a health claim. Breakfast cereal sales were declining. "Heart healthy whole grains" saved the industry.

The fiber recommendation went from 0g to 25-35g daily in the 1970s.

Not because new evidence emerged. Because the grain industry needed a health claim.

Breakfast cereal sales were declining. "Heart healthy whole grains" saved the industry.

Follow the money.

— Sama Hoole (@SamaHoole) October 28, 2025

SAMA HOOLE: We're missing the entire digestive architecture for fiber. But sure, it's essential.

Herbivores have:
- Multiple stomach chambers
- 10x longer intestines
- Cecum the size of trash bags
- Bacteria to ferment cellulose

Humans have:
- One stomach
- Short intestines
- Vestigial cecum
- "Eat 30g of fiber daily"

We're missing the entire digestive architecture for…

— Sama Hoole (@SamaHoole) October 11, 2025

a lot of focus on fiber because carbohydrate-rich diets are the natural diets of mice and those are the animals typically used for microbiome research to study physiology

The metabolic flexibility of the gut.  There's been a lot of focus on fiber because carbohydrate-rich diets are the natural diets of mice and those are the animals typically used for microbiome research to study physiology.  

Her name is Dr. Lucy Mailing.

In the attached clip, microbiome researcher Dr. Lucy Mailing explains why fiber isn't the end all be all when it comes to gut health. So fiber is often over hyped, for example, by doctors like @DavidPerlmutter Cc. @DrRagnar @SBakerMD @KenDBerryMD @FoodLiesOrg @bigfatsurprise pic.twitter.com/XHoRahWTpZ

— REGENETARIANISM (@REGENETARIANISM) October 26, 2023

Hunter-gatherer tribes eat a lot of fruit and really fibrous starchy tubers when there isn't meat or honey or fruit available.  It's more of a fallback food for them.  The research also didn't figure in all the soil microbes when they're eating.  The research got really zeroed in on the fiber and followed that.  That's not to say that adding fiber . . . does help with their symptoms.  Let's not assume that adding fiber is right for everyone.  Sonbergs did a really great study where they had people increase their fiber consumption or increase their fermented foods and fiber did nothing for gut diversity, but increasing their fermented DID INCREASE their gut diversity.  Even more so, fermented food consumption had universal anti-inflammatory factors across all the subjects.  Those were healthy individuals, so it's not to say that everyone with a gut issue is going to respond well to fermented foods.  Yeah, so I think the hype around fiber needs to be tempered a little bit.