>>370130884
It builds up in your body. It can cross the blood braim barrier. 
What you're citing is the lethal dose to instant kill you.
>Dozens of studies have linked aspartame — the world's most widely used artificial sweetener — to serious health problems, including cancer, cardiovascular disease, Alzheimer's disease, seizures, stroke and dementia, as well as negative effects such as intestinal dysbiosis, mood disorders, headaches and migraines.
there's studues that show people who consume aspartame daily in a replace all your daily sugars with aspartame and other artificial sweeteners have negative side effects.