What bothers me is there's no magical "processing" that does anything to these simple sugars. Fructose is... a 20 atom molecule? There's no magical processing that makes that molecule any different inside a fruit or in honey or in corn syrup.
So either the problem is the characteristics of a single food item (ratio of sugar, fiber, fat, etc.), some magical byproduct of processing that makes up a very tiny fraction of the food, or (more likely correct) the ratios that make up the diet as a whole. Carb/fat/protein ratio seems important as does the ratios of which carbs. Demonizing sugar or "refined" sugar seems ridiculous, encouraging proportional consumption makes sense.
Yep, fructose is exactly the same in an apple or in candy. It's not "processing" it what makes it bad. Unless by "processing" you mean isolating it so you eat it without the fiber of the apple.
Fructose doesn't satiate, while fiber does, and it slows down absorption of fructose as well.
For the same reason, fruit juice is pretty much liquid candy with vitamins.
One factor that may be in play here is speed of absorption. "Non-processed" sugars are often inside the cells of the plants and take time to digest and absorb. The result is lower peak sugar concentration in the blood which does not require strong insulin response by the body.
As others have already pointed out, it's the extraction and concentration of fructose (which is what is meant by "processing" in this context) that is so bad.
The perfect example is that it's unlikely you'd have the appetite for eating 15 apples, but it's not difficult to drink 15 apples worth of juice.
So either the problem is the characteristics of a single food item (ratio of sugar, fiber, fat, etc.), some magical byproduct of processing that makes up a very tiny fraction of the food, or (more likely correct) the ratios that make up the diet as a whole. Carb/fat/protein ratio seems important as does the ratios of which carbs. Demonizing sugar or "refined" sugar seems ridiculous, encouraging proportional consumption makes sense.