FREE SCIENCE-BACKED GUIDE
The Missing Carb That Could Be Protecting Your Brain
A free science-backed brain health guide from Austin Perlmutter, MD
You’ve heard plenty about cutting carbs. But buried in the carbohydrate family is a nutrient that may be one of the most overlooked for long-term brain health — and almost nobody is eating enough of it. In this free guide, you’ll learn what dietary fiber actually does in your brain, what the latest research says about dementia risk, and a simple daily blueprint to close the gap starting today.
By entering your email, you’ll receive the free guide plus occasional science-backed brain health updates. Unsubscribe anytime.
MD-authored
NYT bestselling author
Backed by peer-reviewed research
100% Free, no credit card
INSIDE THE FREE GUIDE
What most people get wrong about carbs — and the one your brain actually needs
Five chapters. Plain-language science. A practical blueprint you can start using today.
🌾
What Fiber Actually Is
Why fiber is technically a carbohydrate — and why it behaves nothing like one. Plus: the staggering global intake gap.
🧠
Fiber and the Brain
The gut-brain axis, short-chain fatty acids, dementia risk data, and a 2024 RCT that turned heads.
🔬
Types of Fiber
Soluble, insoluble, fermentable, resistant starch — what actually matters and why whole food still wins.
🥗
Low-Carb & Elimination Diets
An honest look at the nuance: when restricting fiber-rich foods may be warranted, and what the population data shows.
📋
Your High-Fiber Day Blueprint
Simple, repeatable strategies to close the fiber gap — including a food-by-fiber reference table.
THE SCIENCE
Only 5% of Americans meet their daily fiber target. Your brain may be paying the price.
Guidelines recommend 25 grams per day for women and 38 grams for men. The average American gets 10 to 15. An umbrella review spanning more than 17 million people and 33 separate meta-analyses links higher fiber intake to better metabolic health, longer lifespan, and lower risk of a wide range of chronic conditions. The brain-specific data is the most compelling emerging frontier — including observational studies linking fiber to reduced dementia risk and early randomized trials showing effects on cognition via the gut microbiome.
This guide makes that science accessible — and gives you a practical blueprint to act on it today.
"Buried in the carbohydrate family is a nutrient that may be one of the most overlooked for long-term brain health — and almost nobody is eating enough of it."
Austin Perlmutter, MD
MORE THAN A SUMMARY
The science, the nuance, and a plan you can actually use
This guide doesn't just tell you fiber is good. It shows you why, addresses the counterarguments, and gives you a repeatable daily strategy.
🔬
The Research, Explained
Dementia risk data, the PROMOTe RCT, the gut-brain axis, and the non-linear fiber-cognition finding from 2025 — all in plain language.
⚖️
Honest About the Caveats
A frank look at low-carb and elimination diets, IBS nuance, and where the evidence is still evolving — no cheerleading.
🍽️
A Practical Food Reference
A quick-reference fiber content table for the highest-yield foods — lentils, chia, beans, berries, and more — plus the cook-and-cool trick for resistant starch.
MEET THE AUTHOR
Austin Perlmutter, MD
Austin Perlmutter, MD is a physician, brain health researcher, New York Times bestselling author, and educator focused on helping people understand the science of brain health, nutrition, metabolism, and behavior change. He is the co-author of Brain Wash with David Perlmutter, MD.
His work has been featured across major media and read by millions, with a focus on translating complex science into practical steps for a healthier brain and body.
Physician (MD)
Brain Health Researcher
NYT Bestselling Author
Co-author of Brain Wash
GET YOUR FREE COPY NOW
Are you getting enough? Almost nobody is.
Enter your email below and I'll send you the guide instantly.
Medical disclaimer: Statements in this guide have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent disease. Always consult your healthcare provider for individual recommendations before making changes to your diet.