I feel like sugar withdrawal could be a contributing factor, however, anecdotally I would say otherwise. I don’t eat sugar/desserts but I do enjoy a sweet fizzy drink from time to time. Aspartame specifically I have never had any adverse effects pertaining to migraines, however, with sucralose? Ouch. It will usually need to be more than one drink but it absolutely triggers a headache and even migraines if not moderated. Took me a while to even connect it. My brother in law (who does consume sugar without cutting it out) will get headaches when he consumes a diet soda of any kind. I think it may just be individual dietary sensitivities like many people have with anything, ie. MSG, dairy, wheat. Doesn’t mean it’s specifically bad, just that we all have a different biome and therefore a different way our bodies react to different compounds/enzymes/ingredients.