Dr. Heather Sandison, a naturopathic doctor specializing in neurocognitive medicine, has spent over 15 years studying the brain. She emphasizes that what we eat has a significant impact on brain function, particularly memory, focus, and long-term cognitive health. Sharing her insights with CNBC Make It, Dr. Sandison highlighted a simple but effective dietary change that can help maintain brain sharpness: reducing carbohydrate intake and opting for nutrient-dense foods.According to Dr. Sandison, the brain accounts for only 2% of body weight but is responsible for over 20% of the body’s energy expenditure. “You want to give your brain the nutrients it needs to heal, repair tissues, fight toxins, and create neurotransmitters so that it can stay young, sharp, and energized for as long as possible,” she said.