Even people predisposed to diabetes, or with the disease, can eat these foods in moderation. Carbohydrates, especially sugars, are the leading cause of obesity. It doesn't matter where those calories come from, as far as weight is concerned. Many obese people get into trouble with excessive amounts of fat, not sugar or starch. There's no evidence that eating carbs stimulates appetite or leads to more or easier fat storage and weight gain, as some carb-bashers claim.
Sugar makes children hyperactive.
Though for years parents have been blaming a high sugar intake for their children's uncontrollable behavior, studies have found no evidence for this. Sugar in fruit is good, sugar in candy is bad.