Staying hydrated is incredibly important. Dehydration can make you feel tired, impair decision making and also make you feel hungry. So drinking regularly is really important.
Ideally water is the primary source of hydration each day, but I know how boring that can be. So below are a list of acceptable drinks:
Water
Water flavoured with sliced fruit
Sparkling water
Tea and coffee (with small amounts of milk and sweetener if absolutely necessary) before 1 pm
Sugar free soft drinks if absolutely necessary
Avoid fruit juice, sugar sweetened beverages and creamy coffees.