Do sugar-sweetened beverages like soft drinks and fruit drinks cause obesity and diabetes?
The answer may depend on who funds the research asking the question.
An analysis of 60 studies found 26 out of 26 papers that failed to find a link between sugar-sweetened beverages and obesity or diabetes were funded by industry sources, compared to one industry-funded study out of the 34 that did find a connection.
Researchers analysed published studies from January 2001 through July 2016, excluding studies sponsored by competing industries like dairy and bottled water.
Regulations, taxes and nutrition guidance hinge on whether these drinks contribute to health problems while opponents are keeping to question whether the drinks are to blame, the study team writes in the Annals of Internal Medicine.
"If it were truly controversial, you would expect some of the independently funded studies would not find associations," said Dr. Dean Schillinger, lead author of the analysis, from the University of California, San Francisco.
"This industry seems to be manipulating contemporary scientific processes to create controversy and advance their business interests at the expense of the public's health," the researchers write.
Schillinger is biassed and partial, argued by the American Beverage Association (ABA) in a statement, which represents the non-alcoholic beverage industry in the United States.
The ABA countered that he is a paid expert for the City of San Francisco in a suit challenging a law that would require health warning label on advertisements for sugar-sweetened beverages.
Schillinger told that he would not be serving as an expert in the suit if the ABA and other organisations did not challenge the law.
"I can thank them for being paid," he added.
The industry has the right and responsibility to engage in scientific research, the ABA said.
"The research we fund adheres to the highest standards of integrity for scientific inquiry based on recognised standards by prominent research institutions," the statement reads.
"It contributes to the body of scientific knowledge, meets the needs of regulatory agencies and enables consumers to make informed decisions."
The ABA argued that that the new analysis is an opinion piece meant to influence people in areas near San Francisco and Boulder, Colorado, where soda taxes will be up for a vote next week.
"I don’t care if there is a tax or not a tax," Schillinger said.
"I don’t benefit from that, but what I care about is that all my patients in clinic today had diabetes."
The results of the new analysis confirm what previous research found, said Marion Nestle, the Paulette Goddard Professor of Nutrition, Food Studies and Public Health at New York University in New York City.
Nestlé who wasn’t involved in the new analysis said "Big surprise, they found what everybody else has found,"
"If an industry is paying for it or a food company is paying for it, it’s reason for scepticism," Nestle said. Hopefully those results will be replicated by someone without a vested interest, she said.