In a 2014 article on www.mercola.com, Dr. Mercola sheds light as to why the artificial sweeteners added to our “diet” sodas, “health” drinks and other foods can have the opposite effect they are intended for;
“When you eat something sweet, your brain releases dopamine, which activates your brain’s reward center. The appetite-regulating hormone leptin is also released, which eventually informs your brain that you are “full” once a certain amount of calories have been ingested.
However, when you consume something that tastes sweet but doesn’t contain any calories, your brain’s pleasure pathway still gets activated by the sweet taste, but there’s nothing to deactivate it, since the calories never arrive.
Artificial sweeteners basically trick your body into thinking that it’s going to receive sugar (calories), but when the sugar doesn’t come, your body continues to signal that it needs more, which results in carb cravings.”
Check out the rest of the article here: http://articles.mercola.com/sites/articles/archive/2014/12/23/artificial-sweeteners-confuse-body.aspx