One of industry’s main arguments against critics’ targeting high-fructose corn syrup (HFCS) as Public Health Enemy No. 1 has been that HFCS and table sugar are chemically similar. Manufacturers have stated over and over that the most common form of HFCS in use in processed food is at most 55 percent fructose and 45 percent glucose — not significantly different from white sugar’s 50/50 fructose/glucose makeup. If you want to read up on the heated debate about whether this focus on the chemistry is misplaced, feel free.

Now it turns out that the actual amount of fructose in HFCS in particular food products has never been officially disclosed, just assumed. And that assumption, much to the surprise of even the biggest HFCS-is-bad skeptics, has just been proven way off.

Researchers from the University of Southern California decided to test actual brand-name sodas — including Coke, Pepsi, and Sprite — to confirm their exact sugar content and makeup. They found that the HFCS in the vast majority contained far more than the presumed 55 percent fructose: in the case of those three brands, it was actually 65 percent fructose.

Why is this important? It’s because research has shown fructose to be particularly harmful to human health. Unlike excess glucose, which passes through our digestive tract and is excreted, 100 percent of fructose that’s consumed is taken up by the liver. Once there, fructose causes increased fat deposition in the abdominal cavity and increased blood levels of triglycerides — both of which are risk factors for heart disease and diabetes. So, over a lifetime, the HFCS in the 53 gallons of soda per year the average American drinks thus increases their fructose consumption compared to table sugar, and probably adds up to big health problems.