I had a look at their website and their theory seems simple enough. However in practice would you compensate for the non-absorbed starch by eating more subconsciously.
And of course, as with all diet supplements - it must be used in conjunction with a healthy diet and moderate exercise.
I doubt if you JUST took the tablet and nothing else that you would lose weight. If it worked, there wouldn't be any other supplement on the market, and we'd all be "cured"!
IMHO it's the healthy diet and the moderate exercise that does the trick! However I'd be very interested to hear if it helps.
Good luck with it