At present, we believe that the following conclusions are warranted. First, there is no unique relationship between HFCS and obesity. Second, there is broad scientific consensus that there are no significant metabolic or endocrine response differences or differences in health-related effects between HFCS and sucrose. [0]

As others have said, it's an issue of quantity. Consuming 10-30 grams of sugar daily - table sugar, corn syrup, high-fructose corn syrup, or otherwise - does not cause obesity and health problems. The World Health Organization recommends no more than 10% of one's daily calories come from sugar. [1]

The average American consumes ! 125 ! grams of sugar a day, with empty carbs accounting for up to 40% of caloric intake [2]. This 40% includes the simple, 'empty' carbohydrates found in processed breads, cereals, condiments, drinks - which are converted to glucose by the digestive system in minutes.

The amount - not the quality - of sugars in our diet is the problem.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649104/

[1] https://www.who.int/nutrition/publications/guidelines/sugars...

[2] https://www.thediabetescouncil.com/45-alarming-statistics-on...

The problem with HFCS seems to be it's ubiquity and low cost, not its chemical makeup.

My current understanding is sucrose gets converted to glucose and fructose pretty much instantly once it hits your stomach[1].

The difference is, no one dumps a dozen teaspoons of sugar per serving in home prepared food and drink. Where drink and processed food manufacturers carefully buffer their recipes to accommodate the equivalent amount of HFCS.

[1] Read though that low end processed foods and drinks often contain very high levels of fructose.

Here's some counterpoints to the other points made:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3522469/

https://www.ncbi.nlm.nih.gov/pubmed/23181629

https://www.ncbi.nlm.nih.gov/pubmed/23630060