I dug up some info on yacon from a few different sources and condensed it here:
Yacon root syrup is a vegan sweetener derived from the root of the tuberous yacon plant, native to the Andean region of South America.
The root of the yacon plant tastes similar to jicama, but it's biologically closer to the sunflower family.
Yacon root contains no glucose and does not increase blood sugar levels.
For this reason, the syrup often recommended as a sweetener for diabetics or those at risk for becoming diabetic.
According to some studies, yacon syrup also a good source of antioxidants.
It's touted as promoting healthy bacteria that aid in cleansing the colon and regulating the digestive system.
In some countries, such as Brazil and Bolivia, the leaves of the yacon plant are brewed as a tea believed to fight diabetes.
The yacon roots get their sweet taste from their exceptionally high levels of fructo-oligosaccharides (or FOS for short).
In fact, yacon roots are believed to be the greatest producers of fructooligosaccharides in the natural world.
Because the body cannot process FOS
, it passes through the system without leaving behind absorbable sugar compounds. The fibers in FOS pass through the stomach undigested and become fuel for the beneficial bacteria in the intestines (the probiotics).
There is some concern about whether bacon syrup is FODMAP, which are foods that can cause problems for people with IBS and other digestive disturbances.
Yacon syrup has a rich flavor, comparable to molasses, honey or caramel. It also is relatively low in calories, compared to most other sweeteners.
The sweetness is a very concentrated flavor, so it's best to start with a small amount when you add it to a recipe, or to sweeten a beverage such as coffee, tea or lemonade, and add more in small amounts until you reach the desired sweetness.
Yacon is a relatively new sweetener on the market, so it's got a "sweetheart" status in the natural foods world at the moment. Keep your eye out for more research on the subject.