Aspartame is a very evil substance, i did a bit of research on aspartame, and it seems that is causes cancer (what doesnt?) in lab rats in extremely low doses, I steer completly clear of aspartame at all costs. As another poster stated, Dr. Atkins, as well as many others, believe that aspartame inhibits ketosis. So as far as the induction period goes, id advise to stay away :-)