New evidence shows the sugar industry suppressed scientific research that linked sugar to heart disease and bladder cancer in rats.

The Sugar Research Foundation, the group funding the studies, cut the project short and didn't publish the results. Nutritionists caution that sugar, not fat, is largely to blame for many of the problems in our modern diets.

For decades, sugar lobbyists have been taking aim at studies linking sugar and cancer.

When a study last year found that mice on sugar-heavy diets were more likely to develop breast cancer, the Sugar Association – one of the biggest sugar lobbying groups in the US – called it "sensationalised." The group insists that "no credible link between ingested sugars and cancer has been established."

But doctors and researchers claim the sugar industry may have been intentionally keeping research about that link from getting published.

A new study in the journal PLOS Biology reveals how the Sugar Association worked to suppress scientific findings on the harmful effects of table sugar on rodents nearly 50 years ago.

The report details the results of two unpublished studies, known as Project 259, which were funded by the sugar lobby in the late 1960s. Both involved research on the effects of feeding sugar to rats.

In the first study, one group of rats was fed a balanced diet of cereal, beans, fish and yeast, while the other rats were given a high-sugar diet.

The researchers found that the sugar eaters were at greater risk for strokes, heart attacks and heart disease, and had higher-than-normal levels of fat (triglycerides) in their blood.

The second study compared sugar-fed rats with starch-fed rats and found that the sugar-eating rodents were more likely to have elevated levels of an enzyme associated with bladder cancer in humans.

None of that rodent research saw the light of day, though. The Sugar Research Foundation cut Project 259 short and didn't publish any of the results.

"Our study contributes to a wider body of literature documenting industry manipulation of science," the researchers, who hail from the University of California San Francisco, wrote in their report.

In a statement, the Sugar Association denied that allegation, saying the new study is just "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 organisations that are known critics of the sugar industry."

"We reviewed our research archives and found documentation that the study in question ended for three reasons, none of which involved potential research findings: the study was significantly delayed; it was consequently over budget; and the delay overlapped with an organisational restructuring," the group said.

But this is not the first time we've learned that 'big sugar' has gotten in the way of science.

Last year, some of the same researchers found that the Sugar Research Foundation – the former name of the Sugar Association – paid off three Harvard scientists in 1967 to make sugar seem less unhealthy and suggest that fat was the problem in our diets instead.

"The kind of manipulation of research is similar to what the tobacco industry does," study co-author Stanton Glantz said in a release.

Decades of research on sugar since Project 259 have linked sugar consumption to a glut of serious health problems, including high cholesterol, heart disease, and kidney disease, to name a few.

Recent research also suggests that sugar may play a role in tumour growth, but scientists don't think it makes cancer grow faster, and still aren't certain whether sugar consumption has any link to cancer formation.

After years of fuelling up on high-sugar, low fat foods, consumers are finally becoming wise to the problems with sugar that were hidden for so many years.

And the US Food and Drug Administration is, too – by 2021, all nutrition labels will have to include the per cent daily value of added sugars for the first time, while the "calories from fat" column will get scrubbed.

This article was originally published by Business Insider.