EXPOSED: Why there IS a "Unique" American Snus Taste
Quoting from an article by Jeffrey Rose, CMH " American "cigarettes themselves are actually between 8% and 18% sugar, so smokers who puff a cigarette frequently during the day are actually giving themselves blood sugar-raising hits throughout the day. All this contributes to smokers experiencing a slight sugar high from increased blood glucose. As a result of this, many smokers also experience a lessening of appetite.
This may explain why people gain weight after stopping smoking. They are trying to maintain their prior elevated glucose level, which was found to be pleasurable. Any craving that a new nonsmoker might experience is most noticeable in the morning and mid-afternoon, when low blood sugar is no longer blocked by smoking."
Thus each cigarette gives the smoker a "sugar high" as well a dose of nicotine, further enhancing the pleasurable effects of cigarettes with sugar as well as nicotine. This, combined with the eventual nicotine addiction, make it so incredibly difficult, if not impossible, for many people to quit nicotine tobacco products.
The science behind this from what I can tell is still a mystery, but maltol and ethyl maltol double the perception of sucrose, though the molecules only halfway bind into sweet receptor. They can't be considered sweeteners, only sugar flavors/taste modifiers, but they are so popular in ecig blends, maybe it is related.