Grain Brain

The Surprising Truth about Wheat, Carbs, and Sugar--Your Brain's Silent Killers


By David Perlmutter MD

Read by Peter Ganim

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$20.49 CAD

The devastating truth about the effects of wheat, sugar, and carbs on the brain, with a 4-week plan to achieve optimum health.

In Grain Brain, renowned neurologist David Perlmutter, MD, exposes a finding that’s been buried in the medical literature for far too long: carbs are destroying your brain. Even so-called healthy carbs like whole grains can cause dementia, ADHD, epilepsy, anxiety, chronic headaches, depression, decreased libido, and much more.

Groundbreaking and timely, Grain Brain shows that the fate of your brain is not in your genes. It’s in the food you eat. The cornerstone of all degenerative conditions, including brain disorders, is inflammation, which can be triggered by carbs, especially containing gluten or high in sugar. Dr. Perlmutter explains what happens when the brain encounters common ingredients in your daily bread and fruit bowls, how statin drugs may be erasing your memory, why a diet high in “good fats” is ideal, and how to spur the growth of new brain cells at any age.

Dr. Perlmutter’s revolutionary 4-week plan shows you how to keep your brain healthy, vibrant, and sharp while dramatically reducing your risk for debilitating neurological diseases as well as relieving more common, everyday conditions — without drugs. Easy-to-follow strategies, delicious recipes, and weekly goals help you to put the plan into action. With a blend of anecdotes, cutting-edge research, and accessible, practical advice, Grain Brain teaches you how to take control of your “smart genes,” regain wellness, and enjoy lifelong health and vitality.


Your brain…

weighs three pounds and has one hundred thousand miles of blood vessels.

contains more connections than there are stars in the Milky Way.

is the fattest organ in your body.

could be suffering this very minute without you having a clue.


Against the Grain

Maintaining order rather than correcting disorder is the ultimate principle of wisdom. To cure disease after it has appeared is like digging a well when one feels thirsty, or forging weapons after the war has already begun.

Huangdi Neijing, 2ND CENTURY BC

WHEN THIS BOOK first came out in 2013, it challenged the dietary dogma of the day. The premise focused on reducing carbohydrates, eliminating gluten, and increasing the consumption of high-quality dietary fat. Such a protocol flew in the face of the prevailing wisdom of what made for a healthful diet. I pushed the limits not just with respect to severely cutting sugars and carbs and adding more dietary fat, but in promoting ketosis and employing the power of intermittent fasting. This led to mainstream discussions about these topics as they relate to salubrious dietary choices and general habits. I like to think I started a revolution. And it must continue, especially now that I’ve lost my dear dad to Alzheimer’s disease.

In truth, however, I wasn’t the one who ignited this revolution. I didn’t have a global marketing plan back then. What propelled the movement were readers who implemented these changes in their eating habits and experienced positive results. Those results then motivated them to make other favorable shifts in their habits beyond diet. All those little changes added up to immense transformation; the micro grew into the macro. They upped the overall quality of their life and shared their story with others. Nothing is more powerful than the spread of ideas through good old-fashioned word-of-mouth. My hope with this revised edition is to reach both those who read the original work and those who are just meeting me and my ideas for the first time. Welcome. I’ve written this for both audiences, and I hope it speaks to you in ways that empower you to take control—and ownership—of your health today like never before.

I took some heat for my contrarian advice (my advice doesn’t help the wheat and sugar industries), but the results manifested by following the recommendations in Grain Brain made clear the fundamental soundness of its principles. Countless readers who struggled lifelong with a variety of chronic health conditions—from anxiety, attention deficit hyperactivity disorder (ADHD), and brain fog to inflammatory diseases, mood disorders and depression, neurodegenerative decline, diabetes, and obesity—were finally able to shift their health destiny, for the better. You can learn about some of these stories of transformation online at or on my YouTube channel, DavidPerlmutterMD. I’ll also be showcasing more testimonials throughout this book as sidebar boxes (look for “A True GB Story”).

Grain Brain has become a global phenomenon, with more than 1 million copies in print and translated into 30 languages. It continues to astonish me, and I am forever humbled by the opportunity to participate in so many positive health outcomes, reaching people I never could have previously in my private practice. The book’s success has also opened the door for me to travel globally and meet with health-care practitioners, top research scientists, and lay populations alike. One of my most gratifying experiences occurred in 2017 when I shared my views on brain health at the World Bank, a presentation that was broadcasted to 150 sites around the planet. I’ve participated in countless other public and private events, lectures at medical schools, and high-profile media including print and television, to continue to amplify and support the guidelines originally contained in the Grain Brain protocol.

But I must go further with this new edition.

The basic operating system underlying the practice of medicine in America today is myopically focused on treating our ills with highly profitable remedies directed at symptom management.1 Causality is ignored. Preventing disease is derogated and relegated to the province of alternative modalities. Watching our elected leaders debate the merits of funding the ever-changing iterations of a health-care plan designed to treat illnesses presents a poignant irony, as it has little to do with health and everything to do with sickness. But it has become clear that both sides of the aisle enthusiastically agree that Americans must have access to their pills—and lots of them.

From my perspective, getting the word out that people can make simple changes to prevent a disease like Alzheimer’s for which there is no meaningful treatment not only makes sense, but is imperative. The word doctor means “teacher.” And now that so many physicians seem steeped in providing drug remedies, it is the right time to take a step back, review current science, and get the word out that the patients for whom we care can make choices, today, to remain healthy.

A lot has happened in nutritional and brain science since 2013, and publications from our most highly respected academic institutions have now fully validated the principles that I originally put forth in Grain Brain and that I’ll address in this updated edition. Even the U.S. government has modified its dietary guidelines to reflect this research, backpedaling away from endorsing low-fat, low-cholesterol diets and moving closer to my way of eating. Times are a-changin’!

In 2013, certain myths still circulated in health circles like bad rumors. We were still living in a world that considered all dietary fat to be somehow associated with risk for disease (obesity included), gluten sensitivity was a conversation held only in the context of celiac disease, and no scientist dared to push simple lifestyle modifications to stimulate the growth and proliferation of new brain cells. Five years later, we have more evidence to show what contributes to brain decline and diseases like Alzheimer’s.

In the original edition of Grain Brain, I posited that the main reason for avoiding gluten-containing foods was because of their role in exacerbating inflammation in the human body. In this revised edition, we will not only revisit the original research that set the foundation, but we will review newer research that clearly defines the mechanism related to inflammation from gluten. In fact, in 2015, a study published in the journal Nutrients revealed that gliadin, a protein found in gluten, is associated with increased gut permeability in all humans.2 This research was based on the groundbreaking discoveries of Dr. Alessio Fasano at Harvard, who unraveled the mechanism whereby gluten induces these changes in the gut lining. Increased gut permeability intensifies the production of the chemical mediators of inflammation. And make no mistake about it, systemic inflammation—meaning widespread inflammation in the body, including the intestines—is damaging for the brain. This connection between the gut and the brain is a pillar upon which Grain Brain is built.

An important theme that I am going to revisit is how we look at the balance between neurogenesis—the growth and development of brain cells and neuronal tissue—and inflammation:

My goal is to show you how certain habits reduce inflammation while at the same time enhancing neurogenesis, so that rather than destroying brain cells you are sparking the growth of new ones.

One of the most contentious ideas posited in Grain Brain was that people can have significant negative reactions, even neurological symptoms, as a result of being sensitive to gluten. Nonetheless, to this day we continue to see aggressive, and seemingly authoritative, online commentary indicating that if you don’t have celiac disease or a bona fide wheat allergy, there is no benefit to going gluten-free. These pervasive publications indicate that no one is sensitive to gluten except for the very small percentage of individuals who have the autoimmune condition we call celiac disease or who are otherwise allergic to wheat. I can only imagine who supports this kind of nonscientific nonsense, which does such a disservice to so many. There is now universal recognition that so-called non-celiac gluten sensitivity is a real entity. Indeed, as published in 2017 in the highly respected Journal of the American Medical Association, Harvard researchers made it quite clear that non-celiac gluten sensitivity is a common problem and can be associated with not only gastrointestinal issues but even extraintestinal issues as well, some of which involve the brain, as seen in the following table.3

While the general consensus around the ills of too much sugar and carbs has grown, we still have a giant problem on our hands that has not changed: The rates of dementia, including Alzheimer’s disease, continue to rise sharply on a global, massive scale. As Drs. Michal Schnaider-Beeri and Joshua Sonnen wrote in their 2016 paper for the journal Neurology: “Despite great scientific efforts to find treatments for Alzheimer disease (AD), only 5 medications are marketed, with limited beneficial effects on symptoms, on a limited proportion of patients, without modification of the disease course.”4

My mission to end this illness will not finish while I’m still roaming the planet. Brain health has been my passion, professionally, for the past forty-plus years and personally since my father was diagnosed and subsequently died from Alzheimer’s disease—the most common form of dementia that has no treatment, let alone cure, despite the billions of dollars thrown at it in research circles. It now affects one out of every ten people in America aged sixty-five or older. And what doesn’t get any significant attention is the fact that women are affected by this disease twice as often as men. We’ve made some great progress in other areas like heart disease, stroke, HIV/AIDS, and certain cancers. But consider this: Between 2000 and 2014, there was a dramatic reduction in people dying of these ailments, yet during that same time period, deaths related to Alzheimer’s disease increased a staggering 89 percent.5

It pains me to even mention the financial toll of this crisis. To think that we are spending up to $215 billion a year on dementia care in this country—far more than we’re spending on any other disease—is infuriating when we consider that the vast majority of these dementia cases could have been prevented with simple lifestyle modifications early in the life cycle. I should also add that we cannot put a value on the emotional expense to loved ones and caregivers. This year, the global cost of dementia care has topped $1 trillion, and incredibly, this figure is predicted to double by the year 2030.6 That means that right now, global expenditures for dementia health-care exceed the market value of companies like Apple and Google. And if dementia care was looked at in the context of an economy, globally it would be the eighteenth largest economy. Again, this is a largely preventable disease striking a new patient every three seconds.

The numbers are rising in places where incidence of dementia has been historically low compared with Western nations. Based on current projections, Eastern Europe will have about a 26 percent increase in dementia cases by 2050, and in Africa the prevalence will skyrocket by 291 percent. In Central America, the increase is predicted to be 348 percent. This goes to show we’re not looking at a genetic problem. While there are genes that do raise one’s risk for Alzheimer’s disease, purely genetic cases are dwarfed by those from environmental and behavioral influences. Worldwide, the majority of dementia patients live in upper-middle-income or high-income countries, and by 2050, a staggering 73 percent of the 131 million dementia patients will be represented by individuals from the highest brackets of the income scale, as seen in the figure on the next page.7

The idea that lifestyle choices profoundly influence a person’s risk for developing Alzheimer’s disease is not new and was certainly not first proposed in Grain Brain. Our most respected journals, such as the Journal of the American Medical Association, have for many years been publishing research showing that the choices we make influence our brains’ destiny. Case in point: In 2009 researchers analyzed a group of nearly two thousand elderly individuals without dementia who were followed from 1992 through 2006.8 They asked a simple question: What did these folks eat and how much activity did they get? Their findings were compelling. They demonstrated that those individuals who were the most active and had a diet that was mostly “Mediterranean type” experienced a significant reduction in the risk for becoming patients with Alzheimer’s disease. Since that study, numerous others have made the same conclusions, prompting the Mayo Clinic to post an article on its site in 2018 by one of its leading neurologists and faculty members stating that a Mediterranean diet can help protect the brain and reduce the risk of developing dementia.9 As we did in the original book, we will explore in depth how this is possible, but now with more up-to-date understanding and validation of our original contentions. We also know from this study and others that multiple interventions come into play for Alzheimer’s risk, such as physical activity, restorative sleep, and nutritional supplements.

There’s so much to explore, so let’s get to it, starting with a look back to simpler times many millennia ago. I painted this picture previously, but it’s so powerful that it begs to be repeated.


IF YOU COULD ASK YOUR GRANDPARENTS or great-grandparents what people died from when they were growing up, you’d likely hear the words “old age.” Or you might learn the story of someone who got a nasty germ and passed away prematurely from tuberculosis, cholera, or dysentery. What you won’t hear are things like diabetes, cancer, heart disease, and dementia. You also would not hear about numerous people suffering from conditions like anxiety and depression, ADHD, chronic pain, and any of the multitude of autoimmune disorders, from fibromyalgia to multiple sclerosis. These are the ailments of modern life, despite access to modern medicine.

Since the mid-twentieth century, we’ve had to attribute someone’s immediate cause of death to a single disease or condition rather than use the term “old age” on a death certificate. Today, those single illnesses tend to be the kind that go on and on in a chronic, degenerating state and involve multiple complications and symptoms that accumulate over time. Which is why eighty- and ninety-year-olds don’t usually die from a specific ailment. Like an old house in ongoing disrepair, the materials weather and rust, the plumbing and electrical systems falter, and the walls begin to crack from tiny fissures you cannot see. Throughout the home’s natural decline, you do the needed maintenance wherever necessary. But it will never be like new unless you tear down the structure and start over again. Each attempt at patching and fixing buys you more time, but eventually the areas in desperate need of a total remodel or complete replacement are everywhere. And, as with all things in life, the human body simply wears out. An enfeebling illness sets in and slowly progresses until the body finally goes kaput.

This is especially true when it comes to brain disorders, including the most dreaded of them all: Alzheimer’s disease. It’s a modern medical bogeyman that’s never far from the headlines. If there is one health worry that seems to eclipse all others as people get older, it’s falling prey to Alzheimer’s or some other form of dementia that leaves you unable to think, reason, recall, and remember. Research shows how deep this angst runs. Numerous polls taken around the world indicate that people fear dementia more than cancer and other leading causes of death. Fear of death itself takes a back seat to the prospect of dementia. And this fear doesn’t just affect older people. Younger generations begin worrying about their brain health the moment someone in their family or circle of friends shows decline. In the words of my friend and colleague Dr. Dale Bredesen, “Everyone knows a cancer survivor; no one knows an Alzheimer’s survivor.”

There are plenty of perpetual myths about the basket of brain-degenerating maladies, which include Alzheimer’s: It’s in the genes, it’s inevitable with age, and it’s a given if you live into your eighties and beyond.

Not so fast.

I’m here to tell you that the fate of your brain is not in your genes. It’s not unavoidable. And if you’re someone who suffers from another type of brain disorder, such as chronic headaches, depression, epilepsy, or extreme moodiness, the culprit may not be encoded in your DNA.

It’s largely in the food you eat.

Yes, you read that right: Brain dysfunction starts in your daily bread, and I’m going to prove it. I’ll state it again because I realize it sounds absurd: Modern grains are silently destroying your brain. By “modern,” I’m not just referring to the refined white flours, pastas, and rice that have already been demonized by the anti-obesity folks; I’m referring to all the grains that so many of us have embraced as being healthful—whole wheat, whole grain, multigrain, seven-grain, live grain, stone-ground, and so on. Basically, I am calling what is arguably our most beloved dietary staple a terrorist group that bullies our most precious organ, the brain. I will demonstrate how fruit and other carbohydrates—especially those laden with sugars, real and artificial—could be health hazards with far-reaching consequences that not only will wreak physical havoc on your brain, but also will accelerate your body’s aging process from the inside out and screw with its metabolic engines. This isn’t science fiction; it’s documented fact.

It is my objective in updating Grain Brain to provide information that is sound and based on evolutionary, modern scientific, and physiological perspectives. As before, this book goes outside the box of the layman’s accepted dogma—and away from vested corporate interests. I don’t have a lot of friends in industries whose bottom lines I threaten. It proposes a new way of understanding the root cause of brain disease and offers a promising message of hope: Brain disease can be largely prevented through the choices you make in life. So if you haven’t figured it out by now, I’ll be crystal clear: This is not just another diet book or generic how-to guide to all things preventive health. This is a game-changer. At the end of the day, we should all want the same things for ourselves: freedom from chronic conditions that are attributed to how we choose to live. To quote Dr. Bredesen again: “The profound power of lifestyle components to prevent and reverse illness is a gift we have only begun to open.” Years ago, if you had asked me if cognitive decline and even symptoms of Alzheimer’s disease were reversible, I would have said categorically no. Today, I say a resounding yes—if you do the work and change your ways.

Every day we hear about something new in our various wars against chronic disease, particularly with regard to illnesses that are predominantly avoidable through your habits. You’d have to be living under a rock not to know that we are getting fatter and fatter every year despite all the information sold to us about how to stay slim and trim. You’d also be hard-pressed to find someone who doesn’t know about our soaring rates of type 2 diabetes. Or the fact that heart disease remains our number one killer, trailed closely by cancer.

Eat your vegetables. Brush your teeth. Sweat once in a while. Get plenty of rest. Don’t smoke. Laugh more. Be a member of a community. There are certain tenets to health that are pretty commonsensical and that we all know we should practice routinely. But somehow, when it comes to preserving our brain’s health and mental faculties, we tend to think it’s not really up to us—that somehow it’s our destiny to develop brain disorders during our prime and grow senile in our elder years, or that we’ll escape such a fate through the luck of good genes or medical breakthroughs. Certainly, we would probably do well to stay mentally engaged after retirement, complete crossword puzzles, stay socially active, keep reading, and go to museums. And it’s not as though there’s a blatantly obvious, direct correlation between brain dysfunctions and specific lifestyle choices as there is between, say, smoking two packs of cigarettes a day and getting lung cancer, or gorging on French fries and becoming obese. As I said, we have a habit of categorizing brain ailments separately from the other afflictions we attribute to bad habits.

I’m going to change this perception by showing you the relationship between how you live and your risk of developing an array of brain-related problems, some that can strike when you’re a toddler and others that get diagnosed at the other end of your life span. I believe that the shift in our diet that has occurred over the past century—from high-fat, low-carb to today’s low-fat, high-carb diet, consisting primarily of refined grains and other damaging carbohydrates—is the origin of many of our modern scourges linked to the brain, including chronic headaches, insomnia, anxiety, depression, epilepsy, movement disorders, schizophrenia, ADHD, and those “senior moments” that quite likely herald serious cognitive decline and full-blown, irreversible, untreatable, and incurable brain disease. I’ll reveal to you the detrimental effect that grains could be having on your brain right now without your even knowing or feeling it.

The idea that our brains are sensitive to what we eat has been circulating in our most prestigious medical literature. This information begs to be known by the public, which is increasingly duped by an industry that sells foods commonly thought of as “nutritious.” It also has led doctors and scientists like me to question what we considered to be “healthy.” Are carbohydrates and processed polyunsaturated vegetable oils such as canola, corn, cottonseed, peanut, safflower, soybean, and sunflower to blame for our spiraling rates of cardiovascular disease, obesity, and dementia? Is a high–saturated fat and high-cholesterol diet actually good for the heart and brain? Can we really change our DNA with food despite the genes we’ve inherited? It’s fairly well known now that a small percentage of the population’s digestive systems are sensitive to gluten, the protein found in wheat, barley, and rye; but is it possible for virtually everyone’s brain to have a negative reaction to this ingredient?

Questions like these really began to bother me before I first wrote Grain Brain as damning research started to emerge while my patients got sicker. As a practicing neurologist at the time who cared day in and day out for individuals searching for answers to debilitating brain conditions, as well as families struggling to cope with the loss of a loved one’s mental faculties, I felt compelled to get to the bottom of this. Perhaps it’s because I’m not just a board-certified neurologist but also a fellow of the American College of Nutrition—one of the only doctors in the country with both of these credentials. I now serve on the American College of Nutrition’s Board of Directors. I’m also a founding member and fellow of the American Board of Integrative and Holistic Medicine. This enables me to have a unique perspective on the relationship between what we eat and how our brains function. This is not well understood by most people, including doctors who were educated years before this new science was established. It’s time we paid attention. It’s time someone like me came out from behind the microscope and the door to the clinical exam room and, frankly, blew the whistle. After all, the statistics are astounding.

For starters, diabetes and brain disease are this country’s costliest and most pernicious diseases, yet they are largely preventable and are uniquely tied together: Having diabetes doubles your risk for Alzheimer’s disease. In fact, if there’s one thing this book clearly demonstrates, it’s that many of our illnesses that involve the brain share common denominators. Diabetes and dementia may not seem related at all, but I’m going to show you how close every one of our potential brain dysfunctions is to conditions that we rarely attribute to the brain. I’m also going to draw surprising connections between vastly different brain disorders, such as Parkinson’s and a propensity to engage in violent behavior, that point to root causes of an array of afflictions that involve the brain. Newer research is even showing that the road to serious cognitive decline from consuming too many sugary foods doesn’t even have to involve diabetes. In other words, the higher the blood sugar, the faster the cognitive decline—regardless of being diabetic or not!

While it’s well established that processed foods and refined carbohydrates have contributed to our challenges with obesity and so-called food allergies, no one has explained the relationship between grains and other ingredients and brain health and, in the broader outlook, DNA. It’s pretty straightforward: Our genes determine not just how we process food but, more important, how we respond to the foods we eat. There is little doubt that one of the largest and most wide-reaching events in the ultimate decline of brain health in modern society has been the introduction of wheat into the human diet. While it’s true that our Neolithic ancestors consumed minuscule amounts of this grain, what we now call wheat bears little resemblance to the wild einkorn variety that our forebears consumed on rare occasions. With modern hybridization and gene-modifying technology, the 197 pounds of wheat and other grains that the average American consumes each year share almost no genetic, structural, or chemical likeness to what hunter-gatherers might have stumbled upon.10 And therein lies the problem: We are increasingly challenging our physiology with ingredients for which we are not genetically prepared.

For the record, this is not a book about celiac disease (a rare autoimmune disorder that involves gluten but affects only a small number of people). If you’re already thinking that this book isn’t for you because (1) you haven’t been diagnosed with any condition or disorder or (2) you’re not sensitive to gluten as far as you know, I implore you to read on. This is about all of us. Gluten is what I call a “silent germ.” It can inflict lasting damage without your knowing it.


  • "Grain Brain(Revised Edition) is brilliant, accessible, and life changing. By following the scientific advice, you can have a healthier brain and healthier body starting today."—Daniel G. Amen, MD, author of Memory Rescue and Change Your Brain, Change Your Body
  • "There was a time when the notion that diet and gut health could affect brain health was controversial. Today, it is frontline news. The incredible Grain Brain by Dr. David Perlmutter is a significant reason for this change."
    Robb Wolf, New York Times bestselling author of The Paleo Solution and Wired to Eat
  • "If we want to care for our minds, then we have to be mindful about what we eat. Dr. Perlmutter understands the connection between diet and brain health, and this revised edition of Grain Brain teaches us that simple lifestyle changes can make a world of difference."—Maria Shriver, award-winning journalist and bestselling author of I've Been Thinking...
  • "Dr. Perlmutter outlines an innovative approach to our most fragile organ, the brain. He is an absolute leader in the use of alternative and conventional approaches in the treatment of neurologic disorders. I have referred him patients with wonderful results. He is on the cutting edge and can help change the way we practice medicine."—Mehmet Oz, MD
  • "Dr Perlmutter's newly revised and updated Grain Brain is a masterpiece of scientifically accurate information on what leads to dementia and other brain conditions. And most importantly, it lays out a plan for how to stop the insidious brain inflammation that is the result of the wrong diet. The end result will be clearer thinking, improved mood, and an end to worrying about the chance of losing your memory as you get older."—Christiane Northrup, MD, New York Times bestselling author of The Wisdom of Menopause and Goddesses Never Age

On Sale
Mar 1, 2025
Page Count
336 pages
Little Brown Spark

David Perlmutter MD

About the Author

David Perlmutter, MD, is a board-certified neurologist and a Fellow of the American College of Nutrition. He was the recipient of the Linus Pauling Award for his innovative approaches to neurological disorders. With his books now published in twenty-seven languages, Dr. Perlmutter is setting new standards for what healthy lifestyle means around the world.

He is the author of the New York Times bestsellers Grain Brain, The Grain Brain Cookbook, and Brain Maker, as well as The Better Brain Book and Raise a Smarter Child by Kindergarten. He lives in Naples, Florida.

Learn more about this author