Enjoy: Water (and lots of it, preferably not bottled as that's just an environmental disaster), coffee (either black or with full cream), tea. Alcohol in moderation - dry red and white wines, pure alcohols like whiskey, brandy etc.
Avoid: Liquid sugars such as beer, sweet wines, soft drinks, energy drinks, fruit juices, milkshakes. Most sweetened drinks (eg. Coke, Pepsi, Gatorade etc) these days contain High Fructose Corn Syrup (made from genetically modified corn) and should be avoided at all costs, especially by children. The same goes for "Diet" drinks which are filled with chemicals like Aspartame.
If you can, check the added sugar levels in Infant Formulas too as some of these can also be incredibly high.