I wouldnāt rely on the energy required to reduce complex carbs to simple carbs as the mechanism to achieve net 0 (or net negative) energy intake.
I reckon carbs in general, not necessarily just āsugarā (simple carbohydrates), are most culpable with many people unaware gorging Ā on fruit or starchy products is also bad for you.
Yep, starch is just a bunch of glucose daisychained together. Still, it's shocking how much actual sweetener gets shoved into foods you don't think of as sweet.