Despite the fads, “carbs” are not the enemy of health. Unrefined carbohydrates, like those in beans and fruit, are essential. According to Dr. Fuhrman, our brains are designed to run on carbohydrates. That’ll explain why new research in Appetite reveals eliminating carbohydrates, which are broken down into brain-fueling glucose, makes people more forgetful. Low-carb dieters actually preformed worse on memory-based tasks than participants on a reduced-calorie balanced diet; WebMD reports.