Sorry, I've got to butt in here...I've come to learn it doesn't matter what brand of sweetener it is, whether it's aspartame, splenda, stevia, or sugar alcohols. These sweeteners will spike your blood sugar, increase the amount of insulin your body produces, and the extra insulin gets stored as fat.
While I'm not an expert, I do know that
1. Artificial sweeteners will have no or close to no effect on your blood sugar level (depends on the amount of carbs in the product). If they did, people with diabetes would be in serious trouble!
2. It is certainly not the insulin that gets stored. But insulin regulates usage and storage of energy. If it's not needed, the surplus of energy gets stored - in the form of glycogen (short-term storage) or as fat (long-term storage). As you said, high insulin levels which are caused by sugar-rich foods ("spikes") have been linked to supporting adiposity in some studies.