Subsitutes are items that you can use instead of a different item.
In this case a sugar subsitute or "sweetener" is used instead of sugar.
The links on this page can tell you more about differnt sweeteners and how they are used.
The links contain information about honey, and other sweeteners such as splenda and equal.
Many items that you consume or use have subsitutes.
They can be found in everything from diet drinks to pizza or ice cream.