The real truth about sugar isn’t very easy to swallow.

It’s incredibly difficult to avoid sugar in your diet. Globally, we generate over 170 million metric tons of the sweet stuff every year—most which is added to our food.

Despite the fact that it’s everywhere, the nutritional case against sugar is strong, and has been gaining more traction in recent years. Aside from the extra calories that contribute to weight gain, sugar has been implicated in heart disease. Last year, Time reported that the average American spends over $3,000 per year on healthcare-related to problems linked to excessive sugar consumption.

Leaders in the sugar industry haven’t been forthcoming about a lot of this information. Although the sugar industry didn’t outright deny the dangers of their product like Big Tobacco did (paywall), it’s clear that this industry stayed tight-lipped about the effects sugar has on the body.

Last year, researchers from the University of California San Francisco discovered and reported that (paywall) the World Sugar Research Association (WSRO) had funded a large review published (paywall) in the New England Journal of Medicine in 1967 that undercut the evidence that linked sugar to heart disease and put the spotlight on fats instead. It wasn’t until 2016 that the US Agriculture and Health and Human Services departments finally eased their position on fats and started advising consumers to eat less sugar—meaning Americans were getting the wrong health advice for decades.

Now, the same research team has found evidence that the WSRO quietly halted funding on a study that would have highlighted the links between sugar, high cholesterol, and bladder cancer 50 years ago. The company, which was undergoing name changes from the Sugar Research Foundation to the International Sugar Research Foundation at the time, paid for animal research comparing the effects of eating a diet with carbohydrates and one full of sugar, at the University of Birmingham in the UK. However, once the initial data were collected, the group stopped funding the work, and the research was never published. The UCSF team published their investigation on Nov. 21 in the journal PLOS Biology.

The UCSF researchers used a combination of internet archives, records from the University of Illinois Archives, and correspondence kept at the Countway Library of Medicine in Boston, Massachusetts to track down the story of the abandoned “Project 259: Dietary Carbohydrate and Blood Lipids in Germ-Free Rats,” which was conducted between 1967 and 1971.

In the initial experiment, rats and guinea pigs were given either a normal diet with carbohydrates from grains and fishmeal, or a diet high in sugar. Initially, scientists discovered that the sugars changed the composition of the gut flora of these animals, which seemed to lead to higher levels of tryglcycerides. The study also found that animals on a high-sugar diet had higher levels of a chemical called beta-glucuronidase in their urine. Since then, this compound has been thought to be associated with bladder disease in humans, and now considered a consequence (paywall) of having bladder cancer.

In 1970 when researchers leading the study said that they needed 12 more weeks of funding to round out the data, ISRF declined to give them funding. “The sugar industry did not disclose evidence of harm from animal studies that would have strengthened the case that the CHD risk of sucrose is greater than starch and caused sucrose to be scrutinized as a potential carcinogen,” the authors write.

Although the authors admit they can’t say for sure why the work was never published, the fact that the group was aware of these initial findings via documented correspondence with the researchers suggests that the potentially damning data were at least one of the factors. “The kind of manipulation of research is similar what the tobacco industry does,” Stanton Glantz, a professor of medicine at UCSF and co-author of the paper, said in a statement.

The Sugar Association, which is a US lobbying group with ties to the World Sugar Research Organization, told Quartz in response to the UCSF paper: “The article we are discussing is not actually a study, but a perspective: a collection of speculations and assumptions about events that happened nearly five decades ago, conducted by a group of researchers and funded by individuals and organizations that are known critics of the sugar industry.” (The UCSF study was funded by two foundations that promote transparency and science education, The National Institute of Dental and Craniofacial Research, the Nutrition Science Initiative, UCSF, and the National Cancer Institute.) The Sugar Association also noted that the USCF researchers never reached out while they were doing their investigation.

The Association claims that it couldn’t finish funding the study because it was already delayed and over budget while the organization was in the middle of rebranding. The British Nutrition Foundation was supposed to take over afterward, but the Sugar Association is unaware of why that never happened.