The article name is "Scientists are learning why ultra-processed foods are bad for you", the opposite of this thread's title. Everyone's ignoring the elephant in the room: fiber. Fiber locks up calories and makes the body miss a lot of them, or absorb them later in the digestion process. If we reduce the word "processed" to a single action, it's removing fiber. It's turning wheat berries into flour. It's ripping off…
Another way to say this: Eat foods with low glycemic index. Avoid foods that spike blood-sugar levels.
Honey, for instance, has a high glycemic index. Watermelon has a high glycemic index. They will not get you fat the same way cane sugar and watermelon juice will.
A juice made of celery, kale, and spinach, will still have a low glycemic index. But it's still nowhere near as good for you as unprocessed celery, kale, and spinach.