Many of you are probably familiar with Dr. David Perlmutter because of his book Grain Brain. I recently finished his follow-up book, Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life. I can’t quote from it directly because I listened to the audiobook instead of reading a paper copy. (That’s what I do while spending five hours at a time behind a lawn mower on our property: listen to books.) But I can tell you I consider this book a must-read, especially for low-carbers.
I say “especially for low-carbers” because there’s a belief in the low-carb community (which I once shared) that fiber is useless. That belief stems from studies showing no relationship between fiber intake and rates of colon cancer – and that’s why most of us were told to eat our fiber: to prevent colon cancer.
However, the fiber in those studies tended to come from whole grains – which Dr. Perlmutter of course doesn’t want us to eat in the first place, since grains can damage our intestines. Perhaps other fibers do protect against cancer.
But even if they don’t, cancer isn’t the whole story. Not by a long shot. The real benefit of plant fibers is in feeding our gut bacteria. Dr. Perlmutter pounds home that point over and over in Brain Maker: if you want to be healthy, both physically and mentally, you have to feed your beneficial gut bacteria — period, end of story. Those gut bugs want to eat plant fibers. They need to eat plant fibers. In fact, Dr. Perlmutter recommends you fill two-thirds of your plate with plant foods.
Since he’s a hero in the low-carb community, I’m delighted to see this message coming from him. Perhaps some people with a nyaaa, fiber, who needs it? attitude will be inspired to change their minds. As I wrote in some posts last year about why I started adding resistant starch to my diet, if there’s a potential danger in a very low-carb diet, I believe it’s in not feeding the gut bacteria. Dr. Perlmutter is very much on board with a carb-restricted diet, but teaches the reader how to add those all-important fibers without relying on high-starch or high-sugar foods.
As the title suggests, much of the book explains the connection between a healthy gut and a healthy brain. Dr. Perlmutter recounts a number of cases where rebuilding the gut microbiome (with diet or, in a few cases, a fecal transplant) cured patients of depression, or ADHD, or autism, or Tourette’s Syndrome. In some cases, the gut-cure worked after everything else had failed.
But I’m guessing the title is also partly the result of marketing. When your runaway best-seller is named Grain Brain, you’d best put Grain or Brain in the title of your next book. Brain Maker is really about the profound effect the gut microbiome has on the entire body, brain included.
Let’s take an example near and dear to the heart of many readers: weight loss. Dr. Perlmutter describes experiments in which gut bacteria were transferred from thin mice (or thin people) to obese mice. The obese mice became lean. It works the same in reverse, too. When researchers disrupt the gut microbiome of lean mice and transfer gut bugs from fat mice, the lean mice become fat.
As Dr. Perlmutter explains, there are strains of gut bacteria that seem to induce obesity and strains that seem to protect against it. Eating fermented vegetables and other fermented foods helps to populate our guts with protective bacteria. If they’re fed the right kinds of plant fibers, they flourish. But without the right fibers, their numbers dwindle. They can, of course, be devastated by antibiotics. There’s also evidence that certain pesticides and even artificial sweeteners like aspartame can either diminish the number of good gut bacteria or encourage overgrowth of the bad bacteria.
Listening to the book got me thinking about two classes of people: lean vegetarians and low-carbers who lose weight but stall well above their goal. Don’t worry, I’m not going to suggest low-carbers become vegetarians instead. As I explained in Fat Head and quite a few posts, I grew fatter on a vegetarian diet, not thinner. But my vegetarian diet included lots of grains and few of the types of plant fibers Dr. Perlmutter recommends. Perhaps the vegetarians who really and truly eat lots of vegetables (as opposed to grains and soy) stay lean partly by maintaining a healthy gut microbiome – not because they give up meat, but because they eat lots of beneficial plant fibers.
On the flipside, perhaps some low-carbers stall well above their goal weight because they don’t eat beneficial plant fibers. (For the record, I also believe some people are metabolically damaged to such a degree, they can never be lean without starving themselves, which is unhealthy.) If your diet consists of meat, eggs, butter, cream, more meat, a broccoli sprig here and there, plus a side of meat, there’s not much there to feed your beneficial gut bacteria. Toss in some diet sodas with aspartame, and you could be starving the gut bugs that protect against obesity while encouraging the proliferation of gut bugs that induce it.
So what should you be eating to feed the beneficial bacteria? Like I said, I don’t have a paper copy of the book, but the audio version came with a PDF file of recipes. The common ingredients Dr. Perlmutter recommends include onions, garlic, jicama, blueberries, chick peas, Jerusalem artichokes, leeks, fibrous green vegetables of all kinds, plus plenty of pickled and fermented foods. (Apparently the Scandinavians knew what they were doing when they came up with pickled herring.)
I’d add one suggestion of my own: tiger nuts. I understand why people with blood-sugar issues are hesitant to eat the cooked-and-cooled potatoes or green bananas recommended by Paul Jaminet and others as sources of resistant starch, but I doubt tiger nuts will take anyone’s blood sugar on a roller-coaster ride. They’re 40% fat by calories, with lots of fiber and resistant starch — the type of starch your gut bugs love to digest and turn into short-chain fatty acids in the process.
I’ve been eating a small dish of tiger nuts almost daily for a year or so, and I’m pretty sure my gut bugs have never been happier. My digestion is the best it’s ever been, on any diet. I also sleep more deeply, dream more vividly, and wake up more rested than I used to.
But wherever you get your plant fibers, please get them. (Well, not from grains, of course.) As the book explains, gut bacteria account for 90% of all the cells in your body. We evolved with them, and they evolved with us. They’re as much a part of you as your heart and your liver, and nearly as important. Take good care of them, and they’ll take good care of you.
Brain Maker is an excellent guide for doing just that.
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