HealthNotes

If you follow a Paleolithic diet (Paleo diet for short), new research may change the way you eat. The Paleo diet is based on the (supposed) nutritional habits of our pre-agricultural relatives and includes foods such as fruits, vegetables, organic and grass-fed meats, nuts, seeds, and oils. It is widely believed that the cooked, protein-rich meat of this diet was critical to the development of the modern human brain. Yet, there may be something very important missing from the meat-centric version of the Paleo diet—carbohydrates. A new review, published in the journal Quarterly Review of Biology, has found several indications that glucose from carbohydrates was a key player in meeting the energy demands of our prehistoric ancestors’ growing brains. Combing through archaeological, anthropological, genetic, physiological, and anatomical data, researchers made the following points:

• The modern human brain uses up to 25% of the body’s energy, all in the form of glucose. This accounts for an estimated 60% of the body’s total glucose needs. It is unlikely that a low-carbohydrate diet would have allowed for this evolutionary outcome; instead, since carbohydrates are the most efficient source of glucose, it seems they were a necessary part of the prehistoric diet.
• Pregnant and nursing mothers have additional glucose demands and the low-glucose content of a high-protein, low-carbohydrate diet would have likely slowed human reproduction.
• Ancient people may have consumed carbohydrates in the form of starchy roots, tubers, and some fruits and nuts.
• While raw starches are hard to digest, more than one million years ago our ancient ancestors may have started cooking starchy foods, making them easier to digest into glucose.
• Genetic evidence also suggests that humans’ ability to digest starch may have increased over the last million years.

While meat may have played a role in the development of the human brain, the new review proposes that carbohydrates from starchy foods were essential in fulfilling the evolving brain’s increased energy requirements, thereby helping to create the modern brain. So, if you’re following a Paleo diet, you may want to add some cooked tubers to your next meal.

Source: Quarterly Review of Biology