Well when you consider that the GDA for sugar in 5-10 year old's is 85g and a 100ml serving of Tropicana 100% orange juice has 10g sugar. They aren't saying kids can't have fruit juice, just that they shouldn't be drinking it at breakfast. Of course it's all in moderation, if your giving your kid a bowl of Frosties with extra sugar on top, the fruit juice isn't going to do much damage, but also when you consider that the time kids are getting to exercise at school is decreasing and the trend to stay in playing video games after school is increasing, that means they aren't burning off the excess they are taking in.