It can. Food and drinks that are high in added sugars have extra calories and may have few nutrients. Too many sugary foods and sweet drinks can make children feel full and leaves less room for healthy foods. Too much sugar can also lead to cavities if children do not brush their teeth regularly. Sugar is often blamed for behavioral problems and hyperactivity in children. However, studies have not shown that eating sugar makes a difference in the behavior of children with Attention Deficit Hyperactivity Disorder (ADHD).