To be fair, we are also out-living the other stuff that used to kill us, namely infectious diseases. We now have the luxury of dying from heart disease and dementia. That's not so say that there is no room for improvement...
That's true for certain things - maybe people didn't really recognize dementia as such back then, when old and frail people died from some infection before other problems could manifest.
On the other hand, heart diseases are an area where things got significantly worse for no good reason.
We can be safe from common infections (thanks to hygiene) and also not all suffer from heart diseases (by not eating junk), there's no trade-off here.
My point is not that people were doing better then. My point is we could do better given what we know and what we have.
The simple fact that we are debating nutrition on such a basic level ("is something loosely defined as fast food bad?"), shows how fucked we are in that regard.
(Similarly, nutritional concepts, whatever their merits and benefits, that come with a name, be it "atkins" or "paleo", also resemble a pre-scientific worldview based on superstition and vague knowledge. Think "We're building this bridge according to the teachings of Prof. Dr.-Ing. Whatshisname.")
If you remove X cause of deaths in human beings then it will result in a rise of Y cause of death in human beings.
As stated earlier; humans beings must die. If not from infection or injury then from lifestyle factors.
The fact that we have lived to an age whereby lifestyle not predators, infection, war, crime or malnutrition will kill us should be celebrated.
So have a damn burger. You are probably at greater risk from going skiing (no one is proposing limits or awareness about the inherent dangers of skiing). Last time I checked I was not subject to daily discussions about the economic cost of injured skiers.
On the other hand, heart diseases are an area where things got significantly worse for no good reason.
We can be safe from common infections (thanks to hygiene) and also not all suffer from heart diseases (by not eating junk), there's no trade-off here.