A recent study found that diet soft drinks may be better than drinking water for weight loss. But behind the pro-soda research lies a controversial funding source: ILSI Europe, a food industry task force whose board members include representatives from Coca-Cola, Pepsico and Nestle.

According to the Sunday Times, ILSI did more than just fund the research; they also directly paid the researchers — faculty at Bristol University — around $1,000 each. Some suspect that for the price of 250 Starbucks cappuccinos, Coca-Cola bought itself some much needed, positive promotion. This could explain why the findings of the study are in stark contrast to other independent studies that find links between diet drinks and weight gain.

The study, published in International Journal of Obesity, was a review of 5,500 studies, out of which the researchers decided to use just three to reach their conclusion. But Bristol University stands by the study, arguing that due to its publication in a peer reviewed journal “The data and conclusions have been scrutinized by other scientists.”

This isn’t the first time Coca-Cola has faced headwind due to suspicious studies promoting their products as healthy. While fizzy drinks become increasingly associated with obesity and lifestyle diseases, Coca-Cola is eager to call on academia to help repair its tattered image.

Recently Coca-Cola granted a donation of more than $1 million to the University of Colorado —  a university also known for its positive studies on fracking — to fund the Global Energy Balance Network (GEBN). The GEBN promoted the idea that too much focus has been placed on diet and too little on exercise, downplaying the role of sugary drinks in connection to obesity. Its studies received heavy critique, culminating in a return of the $1 million investment and a shutdown of activities of activities by GEBN.

While Coca-Cola struggles to highlight their positive spending, such as the millions of dollars supporting healthy-eating initiatives and sponsoring the Olympics, the Fifa World Cup, and the Rugby World Cup, they’ve also spent $21.8 million to fund pro-industry research and paid $2.1 million directly to researchers. 

Despite these efforts, Coca-Cola is experiencing a noticeable drop in sales on all markets, which is reflected in their recent quarterly revenue. Even if some Americans are buying the company’s health claims for soda, they’re buying less of the soda itself.