Well we've seen hockey stick shaped population level increases in obesity[1] and colon cancer[2] in the last 40 or so years. Doesn't go to say it was caused by aspartame, but I don't think it can be argued we haven't seen population level effects of something.
Colon cancer is correlated to red meat and processed meat consumption. Processed meat(eg:bacon and lunch meat) is a known carcinogen and red meat is a probable carcinogen.
I don't think that's a convincing explanation of this type of broken trend line, unless there was some event in the early 2000s where everyone suddenly decided to eat 10 times as much processed meat...?
It's also not solid logic. Granting that processed meat increases colon cancer risk, that does not go to demonstrate that an observed increase in cancer risk is caused by processed meat. That's affirming the consequent.
[1] https://www.cdc.gov/NCHS/data/hestat/obesity_adult_07_08/obe...
[2] https://gut.bmj.com/content/gutjnl/68/10/1820.full.pdf