Glucose is the main fuel for the brain and body, which is extracted from the food that we eat. When blood glucose levels fluctuate wildly all day on a roller-coaster ride of refined carbohydrates, stimulants, sweets, chocolate, fizzy drinks, juices and little or no fibre to slow the glucose absorption, it's not surprising that levels of activity, concentration, focus and behaviour will also fluctuate wildly, as is seen in children with ADHD.

Some research shows that children with ADHD display poor glucose tolerance and metabolism, meaning that they respond negatively to foods that are high in quick releasing sugars. In a study of 265 hyperactive children, a 5-hour oral glucose tolerance test showed that 74% had abnormal glucose tolerances.