Also true. But arguably it was only possible for those dangers to become known recently. Smoked meats cause cancer. Death by cancer was not so frequent in the past, because fewer people lived long enough to develop cancers that could kill them. Or in other words, they were safe enough at the timescales that people previously operated in.

Also, even though the link between smoked meats and cancer is now as incontrovertible as the link between say tobacco and cancer, the risk is far lower. So it's not like they're wildly unsafe, just kinda sorta of unsafe.

Wouldn't that sort of counter your argument that traditional foods would have discovered the dangers over the ages? Traditional foods could have caused cancer and not been detected, according to your own argument.

"they were safe enough at the timescales that people previously operated in."

If you were a peasant in the 1800s expecting to live till 50, sausages and smoked meat would probably _increase_ your life expectancy due to the additional protein. You would also not live long enough, or eat so much of it as to have a significantly higher likelihood of getting cancer.

The context in which those foods are consumed is different today than it used to be. People live longer and consume way more meat (of every kind) than they used to. If you eat smoked meats and fish (and really any other meats) at the same rates as peasants of 200 years ago, I doubt they'll increase your cancer risk by all that much.

Doesn't the point still stand, though, that you can't use historical usage to prove safety currently (given the change in how we eat food and how long we live)?

Safety is a spectrum really. To give a very binary example we are certain that eating rotten poisonous shark (https://en.wikipedia.org/wiki/H%C3%A1karl) won't kill you because of historical record in spite of eating rotten fish and eating toxic fish separately both being known lethal things.

It doesn't tell us if it is optimal health wise to do such a thing.