I have also read that aspartame can slow weight loss. I have switched to using only Splenda now. Whatever sugar substitute you are losing, you should be having no more than 2-3 packets per day.

If you are concerned this is slowing you down, I'd make the change to Splenda. It actually tastes more like sugar with no aftertaste.

I don't know if it was slowing me down or not, but I want to give this WOE every possible chance to work, so why risk it when there is an acceptable alternative. JMHO.