But if they are making this direct link between ultra-processed foods and increased mortality, then surely it’s these specific substances that are responsible for it?
Not necessarily. Think about it like cigarettes. The nicotine is what gets you addicted, but it is not what kills you. In a similar vein, these additives might cause you in some way or another to consume an unhealthy diet in the most general sense. So the effect can be more indirect.
A single key is as slim as any card…