Quite right Deedaa. People often confuse correlation with causation. After all, it is true to say that shoe size has a strong correlation with reading ability. Seems strange at first, but when you think about it, children of 4 take a small shoe size and usually cannot read, whereas 16 year olds take a large shoe size and can usually read very well. Does anyone think that foot growth causes good reading? No, of course not, the underlying factor is development and exposure to education! Little girls who go to parties get over-excited and often observe behaviour which they then 'try on' at home. The fact that they drank fizzy pop and ate Smarties or cake is incidental. Maddy - is it not the case that your daughter was testing the boundaries and found that her new behaviour was not welcome, so reverted to normal thereafter. There are proper studies of this, and there is nothing in it, although families still like to cling to the idea that there is, perhaps because it externalises the problem. A statistical technique called regression analysis is very useful for partialling out something that's likely to be causative. Unfortunately, our emotional brains go for the 'quick and dirty' route and can sometimes lead us to wrong conclusions. Of course people should strive to eliminate sugary items from their diets for very good reasons, but 'sugar rush' is not one of them