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If you’re a devotee of the modern-day Paleo diet, you might want to make a few changes to your caveman-inspired eating plan after this.
New research has found that carbohydrates have been a key ingredient in the brain’s ability to evolve over time — and experts say that they’re still crucial for brain health.
In a paper published in The Quarterly Review of Biology, scientists say that plant foods containing high levels of starch were essential for the evolution of humans during the Pleistocene period (which lasted about 2,588,000 to 11,700 years ago).
While researchers acknowledge that a meat-based diet was critical to the development of the caveman brain, as previously thought, they argue that easily digestible carbohydrates were also necessary to meet the demands on the growing brain. Specifically, cooked starches increased energy supplies through glucose, which boosts brain development and red blood cells.
Here’s how the scientists’ theory developed: Our bodies begin to convert starch to glucose as soon as it’s in our mouths. Our saliva contains an enzyme called amylase, which starts to break down the starches, but it’s much more effective on those that have been cooked.
Humans have many copies of the amylase gene (more than our closest living relative, the chimpanzee) and, researchers argue, the invention of fire caused a need for us to have more amylase.
Genetic mutations that gave people extra amylase helped them to survive and thrive and, with their ability to break down glucose in cooked starches better, gave them bigger brains.
But the modern-day Paleo diet famously shuns many common forms of carbohydrates, such as cereal grains, legumes, processed foods (like white bread), and potatoes, per PaleoDiet.com. Instead the diet encourages eating grass-fed meats, fish and seafood, fresh fruits and vegetables, eggs, and nuts and seeds, and recommends eating whole grains “infrequently.”
“Without carbohydrates the pre-modern evolutionary species would have been unlikely to thrive,” study co-author Karen Hardy, PhD, tells Yahoo Health. “Starchy food — carbs — is the main energy source for the brain and the body.”
Neurologist James Leverenz, MD, director of the Cleveland Clinic Lou Ruvo Center for Brain Health, agrees. “Carbohydrates are important to normal brain health, particularly during development,” he tells Yahoo Health. Leverenz says carbs are probably more important when we’re younger and still developing, but says you still need them as an adult.
New York City registered dietitian Jessica Cording tells Yahoo Health that changing perceptions of carbohydrates is one of her “biggest battles” as a dietitian. “By getting adequate amounts of carbohydrates, the brain is able to function optimally, which helps the body perform at its peak as well,” she explains.
Carbohydrates aren’t just found in bread, potatoes, and pasta, which is a common misconception. They’re also found in beans, bananas, pears, peas, corn, squash, and many other foods that are considered healthy.
Cording recommends seeking out complex carbohydrates like beans, legumes, whole grains, and sweet potatoes, which slow the breakdown of carbohydrates and promote stable blood sugar (as opposed to the blood sugar spike and dip you can experience with simple carbohydrates like white bread, sweets, and chips).
Of course, too many carbs aren’t great for you either. Cording suggests consuming one serving of complex carbs at each meal to keep energy levels stable, hunger at bay, and your brain performing optimally.
And, if you want to accurately eat like pre-industrialized humans, Hardy recommends incorporating potatoes, starchy seeds, and nuts into a diet that also includes protein.
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