The placebo effect can be a powerful agent when it comes to medical marketing. And so, I suspect, is the case with the Sensa "tastants".
By the time I had started on the Sensa system, I had already spent about a month getting used to consuming fewer calories. Thus, the sprinkles couldn't suppress a hunger sensation that I have already willed myself not to feel, especially given that my radical change in calorie intake did not greatly effect the amount of food I consumed, only the source.
It is my opinion that no amount of Sensa or any other additive or replacement can serve as a substitute for lifestyle alteration, including changes in dietary habits and physical activity level. If a person educates themself about how to properly create and implement a dietary and exercise regimen, unaided weight loss IS possible.