[stouset]

It's meant as a rule of thumb. That level of precision is unnecessary.

Generally speaking, industrially-processed foods are going to be overall less healthy than less-processed alternatives. There are a multitude of reasons this may be so, and between them there's enormous variance in both the size of and our confidence in those effects, not to mention between specific products.

Being overly specific just invites pointless quibbling over those details. Of course, not being specific just started this pointless quibble, so damned if you do damned if you don't.