You need a huge amount of aspertame to cause issues. Sugar is very unhealthy and it’s in everything. I’d recommend sticking to sugar alternatives. If you’re adding sweetener yourself, to coffee or whatever, there are other options though. I like stevia, which you can even grow and extract yourself without too much trouble. Ragardless, unless you’re consuming absolutely massive amounts of aspertame, you’ll be OK. (Maybe switch to water from soda though. That’ll help regardless.)