Both sucanat and stevia are promoted as a "healthy" alternative to refined white table sugar, but that's where their similarities end. Sucanat is a brand name for dehydrated cane sugar juice. Stevia is not sugar, but an extract that comes from the Stevia rebaudiana plant that is 100 to 300 times sweeter than sugar, but has no calories.
Sucanat Is Sugar
Sucanat is an acronym, made up from the first few letters of each word in "Sugar Cane Natural." Unlike white table sugar, which goes through several levels of processing, sucanat is simply cane juice dehydrated into crystals. As a result, it has a strong molasses flavor and deep brown color. It also retains trace levels of nutrients such as iron, calcium, vitamin B-6 and potassium -- but not in amounts significant enough to make an impact on your total daily intake. Use sucanat just as you would any other form of sugar, whether that be in baked goods, hot drinks or sprinkled over fruit and cereal.
Stevia and Reb A
Stevia is not sugar, but a sugar substitute. Before 2008, stevia was only sold as a supplement, but in 2008 the U.S. Food and Drug Administration approved a highly purified form of stevia, known as Rebaudioside A -- or Reb A -- as a food additive. Other stevia extracts, including pure leaf stevia, are still only available as supplements. Stevia is heat stable and may be used for baking, but not in a 1-1 ratio with sugar. If you choose to bake with stevia sweeteners, you must consult the product label to determine the appropriate substitution amount. Some people find that stevia and Reb A have a strong, licorice-y aftertaste.
Effects on the Body
Sucanat raises your blood sugar readily, just like any other sugar product. Stevia, though, does not cause such an increase. Stevia, specifically its derivative Reb A, is often combined with additional ingredients so it looks and pours like sugar. These ingredients could have properties that raise your blood sugar, so read the labels carefully. Sucanat has 15 calories per teaspoon, just like regular sugar, and thus adds to your daily intake. Stevia and Reb A have no calories.
Both Are Processed
Both sucanat and stevia go through some processing to make it to your table. Sucanat's processing is minimal -- the juice is extracted from sugar cane and dried. Supplements sold as stevia extract have undergone less processing that Reb A stevia products, which are "purified" before being sold in packets or incorporated into soft drinks, yogurts and sweets.
Health and Safety
Too much sugar, in the form of sucanat or white table sugar, can lead to obesity and inflammation. The health implications of consuming stevia or Reb A regularly are not fully understood. Although the FDA has designated it "generally recognized as safe," some groups, including the watchdog organization the Center for Science in the Public Interest, are concerned about animal studies that tie stevia to infertility and DNA mutations. CSPI, in particular, has called for more testing on stevia's safety.