And, the opposite for a diet that is, well, the opposite. “A low carbohydrate recommendation for both brain and total body health is supported by both history and science,” he says. “Historically, humans have never had access to any meaningful dietary carbohydrate; throughout our 2.5 million years on this planet, the foods we consumed were either high fat and protein animal products, providing the most efficient sources of calories, or high fiber, as well as extremely low carbohydrate plants and plant products.” In other words, we were not put on this earth to eat that neverending Olive Garden breadstick basket after all.
But that whole Cave Woman (and Man) thing was a gazillion years ago, so shouldn’t our body’s extreme adaptability be up to speed when it comes to our newfound modern diet? Eh, not quite, says Dr. Perlmutter. “The shift in dietary pattern that began with the advent of agriculture in the past 10,000 years has occurred at a rate far too rapid to allow any significant adaptive change in our genome,” he explains. “And keep in mind, while 10,000 years sounds like a long time, it means that for virtually 99.9 percent of our existence as humans, we've been low-carb, high-fat.”
The other question this immediately brings up is one of energy — we need carbs and sugar for fuel, right? While some MDs and RDs would say yes, without a doubt, Dr. Perlmutter disagrees. “We've all been schooled that the brain "prefers" to burn glucose as a fuel. In reality, the most efficient brain "super fuel" is fat, allowing far better ATP production with reduced production of damaging free radicals,” he says. What’s even more alarming, and the main focus of Dr. Perlmutter’s new book, is the destructive aftermath in the brain that indulging in a wheat-and-sugar-laden diet can cause: “Current science clearly correlates even modest increase in available glucose in human physiology with dramatic and clearly detrimental changes in the brain,” says Dr. Perlmutter. “Even slight elevations of blood sugar — well below the threshold for diagnosing diabetes — very directly predicts the future risk of developing dementia, as was recently described in the prestigious New England Journal of Medicine."
How could that unassuming mini-cupcake wreak a whole lot of havoc on your brain? “Elevated glucose does its damage by binding to proteins in the body in a process termed glycation,” explains Dr. Perlmutter. “And when proteins are glycated, this directly damages brain tissue, likely by dramatically increasing the production of damaging chemicals called free radicals. In fact, glycation of proteins may increase the production of damaging free radicals as much as 50 fold.”
Of course, when you are a 20- or 30-something, Alzheimer’s might not be on the top of your got-to-watch-for-this list. But, according to Dr. Perlmutter, now is the time. “The sobering statistics of Alzheimer's reveal that if you live to be age 85 years old, your risk of developing this condition are 50/50. That's a flip of a coin,” he says. “Any family history of the disease will increase your risk, but you can absolutely reduce your risk by maintaining control of your blood sugar. That means adopting a diet low in sugars and carbs. You can change what may have been your genetic destiny by making simple lifestyle changes.”
And, research shows that your brain truly is what you eat. “Mayo clinic researchers have now concluded that, in sensitive individuals, a gluten-free diet opens what would otherwise be a very narrow window in terms of actually treating dementia,” explains Dr. Perlmutter. “Gluten consumption, in as much as 30 percent of the population, induces inflammation, the cornerstone of Alzheimer's and other degenerative conditions of the brain.”
“There is absolutely no need for grains in the human diet. Grains do not contain anything unique that we as humans require,” says Dr. Perlmutter. “Dietary fiber is well-supplied by vegetables as are the various B vitamins. It's important to keep in mind that for more than 99 percent of the time we have walked to planet, we've been virtually grain free.” Here’s how Dr. Perlmutter suggests keeping you — and your brain — in tip-top shape:
Limit total daily carbohydrate consumption to 60-to-80 grams. “This means reducing or eliminating consumption of the obvious carbs like bread and pasta and keeping in mind that fruit and fruit juices are aggressive sources of sugars,” he says. Aggressively increase available fats like coconut oil, olive oil, grass-fed beef, wild fish, and avocado. “Fats are your brain's friend. It's the carbs that kill,” he says. Self-proclaimed carb and sugar addicts, fear not. “Fundamentally, it is never too late to adopt these recommendations,” says Dr. Perlmutter. “Contrary to what we used to believe, the brain actually retains the ability to regenerate, and this occurs throughout our lifetimes, well into our 80s and 90s.”