A couple years ago I worked on a market research contract for a food grower that tried to answer the opposite, "what does all natural mean" (or some set of synonyms)?
Turns out it's virtually impossible to define it.
Here was one of the exercises we went through:
1) Take an orange, grown in the wild without being touched in any way by the hand of man.
2) If you eat that orange, are you eating something that's "all natural"?
3) If you squeeze that orange, and drink its juice, is it still "all natural"?
4) If you strain the juice to eliminate pulp, through a handwoven cloth (or a mat of grass or some other "all natural straining device") is it still "all natural"?
5) If you heat the juice and drink it, ie cook it, is it still "all natural"?
6) How about if you heat it long enough to boil off some of the water?
7) How about long enough to boil off all of the water?
8a) What if instead of boiling you simply dry out the juice in the sun?
8b) What if in addition to boiling it, you dry the remains in the sun?
9) What about drying it in an oven?
10) Suppose I take the dry particles left and through any conceivable natural operation sort them by density? Say, putting the particles into an all natural basket and shake it vigorously until my arms are tired?
11) Now how about I remove particles of a certain density? Is the remaining product natural?
12) Now suppose I add water to the remaining sorted particles, fresh from a mountain spring.
13) Suppose I do the same (#1-12) with other plant sources?
14) Suppose I mix the results into either a mix of powders or a mix of reconstituted liquids?
This is an actual replication of a process for producing an artificial sweetener (not with fruit, but a different plant source). That sweetener is generally not called "all natural" but the process is more or less the above.
At every point in the process we haven't done anything that's not natural. There's some analogy to every step that you probably have to do with any food source to make it edible. Nobody thinks squeezing, chopping, cutting, cutting plants creates a processed food. Or straining liquids or really any of the above. We've been doing all of the above as a species since before writing.
But many people think the result of the specific combination of the above, #14, is a "processed food".
How about cheese? Most cheese, even modern cheese is just milk and bacteria in a controlled spoilage environment. As natural as dirt. And in general the result of very few steps.
Defining "processed food" from "natural food" ultimately ends up trying to set some kind of arbitrary definition delineating the two -- "processed food is any food that has undergone more than 3 processing steps" I have news, chopping and peeling fresh picked garlic takes more than 3 steps.
1) Wash the dirt from the bulb
2) Dry the bulb
3) Remove the outer layers of onion skin
4) Separate the cloves out of the bulb
5) Cut the hard connective bits
6) Peel the layers of onion skin from the cloves
7) Chop to size
Now if I include it in a recipe I'm including it in even more processing steps. I may boil it, grill it, bake it, or some other cooking process.
I may strain it from a broth if all I care about is the flavor.
Before I can actually get the garlic into my mouth, through even an elementary recipe, I've had to process it at least 8 times, likely a dozen.