Whereas the label 'fruit juice' is generally reserved for beverages that are 100% fruit juice; similar to making your own homemade juice, 'fruit drinks' or 'juice drinks' are often no more than flavoured water that has been artificially colored and packed with added sugars. In many cases, these supposedly healthy alternatives to fizzy drinks (sodas) consist of no more than 5% juice.
While the term juice drink is perfectly legal, for parents, this description is completely misleading. Implying that these drinks are actually a healthy choice for children. In fact the words flavour and flavoured make things even more confusing. The word 'flavour'as in 'orange flavour' means that there is no orange in the product whatsoever. Flavoured as in 'strawberry flavoured orange juice' means that some of the named fruit is in the product, but not much (as little as 0.5 per cent strawberry powder).
What must be the worst ingredient in many juice drinks is high-fructose corn syrup. This is a substance that is made by changing the sugar (glucose) in cornflour to fructose (another form of sugar), and because it extends the shelf life of processed foods and is cheaper than sugar, it's commonly used as a sweetener.
The problem with this kind of sugar is that it's addictive ( It's the reason why children crave certain sweetened foods and drinks) and your body converts high fructose corn syrup into fat more rapidly than any other sugar. In the case of juice drinks, since the fructose consumed is in liquid form, the negative effects are significantly increased. Consequences are elevated bad cholesterol, diabetes and weight gain.
Many parents then turn to pure fruit juice, which is without question, better than the juice drinks. But that does not mean children should be drinking lots of it either.
Fruit juice actually resembles a passing relationship to fruit. A lot of the fruit's nutritious good stuff is left behind during the juicing process. Juicing also makes the sugar in the fruit more accessible to the body. The sugar concentration of fruit juice is similar to sodas (even though many juices commonly have 'no added sugar' printed on their labels, these beverages still contain large amounts of naturally occurring sugars).
Of course, fruit juices and fruit drinks are not in the same nutritional league as fizzy drinks, but the fact that they are so sugary means they can cause problems. For example, sugary acidic nature of juice makes, too much of it, is dangerous to our teeth.
Children therefore should consume just one glass a day to minimize the risk to teeth. If I may recommend, the best drink for children should be water. It may not make you popular, and it's not cool but it's the best drink for you and your family. Do also check which food additives to beware of!