There's one problem you face with issues like this. One reason it took so long to prove, beyond significant doubt, that cigarettes cause cancer is because it's

There's one problem you face with issues like this. One reason it took so long to prove, beyond significant doubt, that cigarettes cause cancer is because it's something that happens over many decades and with high variance. Fewer than 20% of smokers will get lung cancer over their whole lives. You cannot experimentally prove side effects that happen only over such prolonged periods of time. So you're left with observational correlations that, to this day, are even scrutinized by some eccentric scientists. When you look at society today, it's going downhill in terms of overall health in a multitude of ways across both the physical and mental/psychological domains. Lowered testosterone, increased obesity, increased mental illness, decreasing IQs [1], and so on endlessly. And if something like e.g. processed foods ends up being one of the factors in this, it may well be another one of those things that's basically impossible to actually prove - outside of extremely long-term correlations which can be endlessly challenged, exactly like this article is doing. And the correlations in this case will be even easier to challenge. Like you mentioned processed foods are enjoyable to eat. They're made to generate profit and so hone in on every little receptor, desire, and impulsive (or even addictive) tendency in our bodies. People are only going to avoid this if they're already substantially health conscious, so even observational correlations can be trivially challenged. So how can we ever hope to prove anything, especially when there may be every reason to expect absolutely zilch will show up in short controlled experimental trials? [1] - https://www.sciencedirect.com/science/article/pii/S0160289623000156 https://www.sciencedirect.com/science/article/pii/S016028962...