"Glycerine is included as a carbohydrate on most nutritional labels even though it is
really a by-product of the metabolism of fat. However, glycerine does not affect insulin levels or blood
glucose. This means that while it has calories, it will not negatively impact the body in ways that will disrupt
ketosis. You should still count the calories you are consuming from this product, since even a low
carbohydrate diet needs some calorie control, but you do not need to worry about disrupting ketosis
because there is no evidence that glycerine effects either insulin or blood sugar, which is the way that
normal carbohydrates disrupt ketosis. "
From Naturally ripped news,
http://www10.netrition.com/cgi/article_display.cgi?magazine_id=RIP&issue_number=7&article_id=4
On a low carb diet, glycerol will be mainly converted to glucose in the liver, but the absorption and conversion is so slow that the impact on insulin secretion and glucose levels is a non-issue for most people.