Coca-Cola has been at the helm of a number of sugar-related research projects, but some could never see the light of day, according to a new study.

A recent study - published in the Journal of Public Health Policy - highlighted the drinks company's involvement in university studies in the US and Canada, and how they held all the power when it came to approving and potentially blocking the research.

Dr Simon Thornley, a senior lecturer in epidemiology and biostatistics from the University of Auckland wasn't surprised to hear of such an agreement, especially within the sugar industry.

"The sugar industry is putting a lot of effort in to deflecting the information that sugar is a problem."

He told Stuff, agreements between funders and researchers, in which they "want to see the results before they get out", are quite common.

"I'm sure the sugar industry has a lot of influence when it comes to what research goes out and which research they tend to sponsor."

Within those agreements, they found the inclusion of language that allowed the company to "review research in advance of publication" and gave them "control over study data, disclosure of results and acknowledgement of Coca-Cola funding," as stated in the study.

Some of the agreements analysed even gave the company the ability to "prevent publication of unfavourable research", however, no evidence of them enacting this clause was found, researchers said.