Comment by tugdual

The reason we're conflating them is because there is a strong correlation between "highly processed food" and "designed recklessly". If you look at Carlos Monteiro (The pioneer in this domain) he operationalized it with the NOVA metric. NOVA 4 being the closest to what you're talking about:

"Industrially manufactured food products made up of several ingredients (formulations) including sugar, oils, fats and salt (generally in combination and in higher amounts than in processed foods) and food substances of no or rare culinary use (such as high-fructose corn syrup, hydrogenated oils, modified starches and protein isolates)..." [1]

[1] https://en.wikipedia.org/wiki/Nova_classification

I highly recommend Chris van Tulleken's Ultra-processed people for a more indepth read on this fat correlation (excuse the pun :))