Putting aside the vague hand wavy definition of what "highly processed foods" literally means, my suspicion is that there are two things making processed food worse for you.

I've heard drinking juiced fruits is worse for you than eating the equivalent fruits, as the sugars in the fruit are wrapped in fiber that make the sugars "slow release" into your body, and those are broken down when juiced so the sugars hit you at once. I suspect processed foods "mainline" nutrients in ways that unprocessed foods don't.

Secondly, I think a lot micro-nutrition is ignored when comparing processed food, like the fat, carb, salt, etc is equivalent between potato chips and, say, a baked potato with butter, but there are a lot of small things that our body needs that are not part of that equivalence. At least for me, when I eat potato chips I eat more because they never quite satisfy me. I suspect this is because the micro nutrition is cooked or processed away, so I end up eating more carbs because it's not quite giving me all what I need, just the big macro needs.

The lack of fibre also contributes to lack of satiety which is another driving factor that makes people eat more processed food.

The potato chip satiety issue is also investigated in a few studies. Baked potato is some of the most satiating foods. But when you fry it in oil it just does something to your brain that makes you crave for more

https://www.medicalnewstoday.com/articles/324078#boiled-or-b...

I agree. I think there is a third thing: processed foods are more likely to contain additives like colorants, emulsifiers, preservatives and stabilisers that humans have been eating for decades rather than centuries so we don’t have the same body of knowledge about them or their health-related impacts.

The chips not satiating you is more likely to be the effect of the obligatory seed oils in chips; IIRC the linoleic acid that they are high in impedes satiety (and also promotes inflammation).

100% this. There is a wonderful book called The Dorito Effect that goes into this in more detail.

> when I eat potato chips I eat more because they never quite satisfy me.

This is why I have paper bowls. Pour out a portion of chips. Eat that. If you're not satisfied after eat something _else_. This is probably as much about ingredients as it is about packaging and delivery.