> it's really hard to find reliable information as to what actually happens since the internet is filled with FUD websites claiming aspartame gave their brother/grandma/cat/chair cancer.
The burden of proof should probably be on the side of those asserting safety of novel food components, and if that means waiting a full generation for the data to come in, so be it (note that animal tests don't really tell us enough, because metabolism doesn't seem that well conserved between species; there are plenty of things that humans can eat safely that animals can't and vice versa)
Human metabolism and our food has coevolved over thousands of years, and we have evidence in the fossil record that shifts in diet (e.g. agriculture, pastoralism) had negative impacts on human health (worse teeth, shorter, weaker bones) until either our genomes or microbiomes adjusted.
If you decide to consume large quantities of novel ingredients in combinations that no humans have ever eaten before in our evolutionary history, then sure, it may turn out just fine—but metabolism is an intricate dance and there are a lot of ways to screw it up.
"Eat food, not too much, mostly plants." and "Don't eat anything your great grandmother wouldn't recognize as food." seem like sensible advice for people who can afford to follow it [1].
[1] https://www.webmd.com/food-recipes/news/20090323/7-rules-for...