As a former Diet Cokeaholic, I can relate to you caffeine withdrawal problems. The best way I found to break the habit is to simply go as long as you can stand it, then have one (that was ONE) small (that was SMALL) cup of your current poison. Then go as long as you can again. Take aspirin if the headache gets too bad. Aspirin always worked better for me than Tylenol or Advil for caffeine head. Don't worry at this point about the little bit of caffeine and aspartame you are consuming. We're only talking a couple of days here, and only in small amounts. It didn't effect me any. I lost 8 lbs. during induction despite weaning off the Coke slowly.

Do this for about three or four days and then you can drop it all and go caffeine free. Oh, by the way, Diet Rite Rocks! How do I know? Been there, done that, got the t-shirt, took it back (it was too BIG!)