Children are not born with a long attention span; they develop the trait as they grow and mature. The ability to sit still and focus on an activity for long periods is much more likely and expected in a preteen than in a toddler. External factors may play a role in attention span, however, including the amount of sugar your child eats.
Sugar and Glucose Levels
Sugary foods cause your child's blood sugar levels to spike after eating, which can affect her behavior. The high glucose levels associated with sugar and refined carbohydrates can give your child a boost of adrenaline, sparking a period of hyperactivity. The National Institutes of Health defines hyperactivity as a combination of increased activity and distractability, which reduces the attention span. Usually, after a "sugar high," your child's blood sugar will drop abruptly, bringing the "crash" -- a period of lethargy, irritability and decreased movement. After the crash, your child's attention span may improve. Avoid giving your children sugary snacks at night to help them get a good night's sleep so they will wake up feeling refreshed.
Anecdotal or observational evidence suggests that sugar has a negative affect on attention span, but the scientific facts do not always support the claim, according to Jacquelyn Rudis, author of a Beth Israel Deaconness Medical Center publication on the topic. Rudis suggests that parents expect that their children might become hyperactive after consuming sugar due to stories the adults have heard about a possible link, but that research does not necessarily follow this hypothesis. Researcher M. Wolraich studied children who followed a variety of diets containing sugar and artificial sweeteners and reported the results in "The New England Journal of Medicine" in 1994 and the "Journal of the American Medical Association" in 1995. Wolraich found that no pattern of shortened attention span developed after feeding the children sugar, but acknowledged that children who were already diagnosed with attention deficit disorders might metabolize sugar differently, causing some variation in behavior.
Sugar may not be the reason your child shows signs of a reduced attention span after enjoying her favorite candy. Artificial coloring could be the underlying reason in some cases. Children who have food allergies or sensitivities may react to food colorings and other chemical additives. Irritability and impulsivity, both of which affect attention span, may be signs that your child is sensitive to the coloring in the candy or snack food, and not necessarily the sugar.
Your child's attention span may be affected not just by the sugar he consumes at certain times, but by the circumstances in which he is eating sweets. Holidays like Halloween and Christmas are filled with sugary treats, but the overall excitement associated with the occasion may also factor into a reduced attention span.