Sucrose metabolizes faster and more efficiently than HFCS. That explains a great deal about why people drank gallons of pop 35 years ago and didn’t gain weight like they do today.
Sucrose needs to undergo catalyzed hydrolysis in the digestive tract before it can be absorbed as the glucose and fructose which results. This adds time after ingestion before the associated rise in blood sugar is seen. HFCS is pre-hydrolyzed, can be immediately absorbed, and has more fructose to boot.