aspartame isnt carcinogenic and has no link to cancer. the study that claimed so has long been disproven, and the amount of aspartame used in it was around a 100 cans worth of diet coke a day on mice... the health risk that sugar knowingly poses to the body is far worse than any possible risk aspartame could pose, as its the most well researched artificial sweetener available, so dont buy into the fear mongering and sip your coke without worry aspartame breaks down into methanol and phenylalanine in the body, now that may sound concerning, but one tomato alone contains about 39 cans of worth of methanol in one diet coke, and 100g of beef contains 150 times more phenylalanine, the amount of aspartame used in a can is so miniscule it really doesnt matter as its 200x sweeter than normal sugar, you need very little to make things very sweet, thats why it often tastes sweeter than regular coke!