I often nibble on a cinnamon stick because first of all I like the taste and the smell and secondly it seems to help in weight loss. How comes that cinnamon sticks seem to taste sweet, even though there is no added sugar involved?
The reason it tastes sweet is the presence of sugar, ie because it is sweet. Cinnamon is thin tree bark, and it is not uncommon for tree bark, or the layer near the bark to be sweet because of sap. Birch is another example of a tree that is sweet, you can suck on a peeled birch branch for the same reasons as stated in your question.