Yes it is well documented that the artificial sweetener aspartame is associated with headaches in quite a few individuals. You could take splenda / sucralose and it is not known cause any headaches as a side effect. If you are not on too much of the higher side on the weighing scale you could continue with sugar and try and reduce its intake to the minimal required. and try regular exercises and low calorie diets.
Splenda has caused nagging headache in some cases although it is not as well documented as it is with aspartame. Splenda is not just sucralose it is chlorinated sucralose. So if you are not diabetic i would suggest you to avoid all artificial sweeteners and be physically active and exercise dietary control to lose weight.
I get chronic cluster headaches due to a facial injury, and I do have to avoid aspiritame because it will cause migraines or cluster headaches for me. I bought some concentrated grape juice the other day and drank 2 glasses of it the night before last, and yesterday I had a MASSIVE cluster headache, puking and dizzy and tunnel vision and excruciating pain and the whole nine yards. Today I got the container out of the recycling and sucralose was on the label, so I'll have to add that to my list of "be wary of this". :( Aspirataime was so much easier to check for because it would have that swirley Nutra-Sweet logo on the front.
Aspartame is metabolized or broken down by the body into substances that may trigger some chemical reaction in the neurons and cause headaches.In some cases, it was shown to have decreased seizure thresholds among those with seizure disorders.There are some persons who are sensitive to aspartame (as in the case when they take diet cola) while others are not.This may explain varying conclusions on aspartame and headache occurrence .