Many parents limit sugary foods, thinking they cause hyperactivity. It's right to restrict these treats, but the reasoning is wrong. These high-calorie foods offer little nutrition and can lead to obesity and other problems, but no scientific evidence says sugar causes hyperactivity. Sugar can provide a short-term energy boost, but that isn't the same as hyperactivity. The children at a birthday party acting like little tornadoes probably has more to do with the excitement of being around other kids, rather than the cake. And that unruly child in the grocery store throwing a fit with a sucker in his mouth and candy clutched in each fist? His parents probably haven't set appropriate behavior limits, and they most likely give him what he wants -- which is more candy.