Photo courtesy of Hachette Book Group Canada Image by: Photo courtesy of Hachette Book Group Canada
What happens when you eat carbs?
When people consume carbs, the glucose level in their blood becomes elevated, and that glucose is toxic, according to Dr. Perlmutter. Why? "Glucose fundamentally releases inflammation and the production of chemicals called free radicals, which oxidize our brains, our DNA, our fats and proteins, and basically rust our body," he says.
If you continue to eat carbohydrates all the time, you'll have a persistently elevated level of blood sugar. That blood sugar binds to your proteins, resulting in inflammation and free radicals in a process called glycation, the cornerstone of brain degeneration, explains Dr. Perlmutter.
Could cutting carbs reduce the risk of Alzheimer's?
No Alzheimer's cure exists today, so Dr. Perlmutter began examining the link between blood sugar levels and dementia in an effort to prevent the disease. "In 2012, the Journal of Alzheimer's Disease published an incredible study which showed that those individuals who ate more carbohydrates had an 89 percent increased risk for becoming demented," says Dr. Perlmutter. "And those individuals who ate more fat had a 44 percent risk reduction for becoming demented. We know how to prevent Alzheimer's today—it's dietary changes and lifestyle changes."
Low-fat is the enemy
The low-fat diet trend encouraged North Americans to cut the fat from their diets. The problem, according to Dr. Perlmutter, is that those popular low-fat foods were also very high in carbs. "Within 10 years, the rates of diabetes tripled," he says. "Diabetes doubles your risk for Alzheimer's." But this knowledge should be empowering, not frightening. Dr. Perlmutter points out that risk factors can be mitigated with a changes to our diet.
Carbs are addictive
"You are addicted to carbs, as you could be addicted to cocaine," says Dr. Perlmutter. "It's the same parts of the brain." And don't think you're off the hook if you choose whole grain bread, either. According to Dr. Perlmutter, whole wheat can be just as bad as eating a candy bar, if not worse. Why? Whole grain bread has a high rating on the glycemic index (a scale that ranks carbohydrate-rich foods by how much they raise blood glucose levels).
"When you eat whole grain bread, you're pounding your body with a surge in blood sugar, and it stays elevated for a long period of time," says Dr. Perlmutter. "That's devastating because that's a longer time for sugar to bind to protein, leading to that process called glycation." What about going gluten-free? Gluten-free products can still be high-glycemic index foods, so they should also be avoided when possible, says Dr. Perlmutter.
What can you eat?
Dr. Perlmutter recommends eating lots of healthful fats to help your brain. He endorses noshing on aboveground vegetables, grass-fed beef, wild salmon, nuts, seeds, olive oil and avocado. The more fat you eat in place of carbohydrates, the thinner you will be, according to Dr. Perlmutter's philosophy. "When you eat fat, insulin is down-regulated and it is a signal to the body to get rid of fat," he says. Avoid man-made fats like trans fats and hydrogenated fats, but any natural fats—even saturated fats like butter—are on his "good list." While sugar-rich fruit juices are a definite no-no, you can have whole pieces of fruit (as they have fibre), says Dr. Perlmutter, but only within reason.
When is it too late to reverse the damage caused by carbs?
"It's never too late," says Dr. Perlmutter. "The brain has a lot of what we call ‘plasticity,' which means it can rewire itself and regenerate itself and it can grow new brain cells. So we see wonderful changes in people in their 90s who finally kicked the carbs and added in the fat," says Dr. Perlmutter. And what if you only want to cut the carbs a bit? "Halfway measures progress halfway," he says.
Learn more about Dr. Perlmutter's findings in his book, Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar—Your Brain's Silent Killers. Before starting any new diet or lifestyle regimen, always talk to your doctor, especially if you have any health issues like diabetes.
For more information on nutrition, check out our stories on gluten intolerance and celiac disease.