How do we provide our growing global population with healthy diets, in ways that don’t harm the planet?

It was a landmark report, meant to recast the way we think about humankind’s approach to food—addressing global nutrition deficits and the agricultural impacts of climate change alike.

But when the 49-page, Harvard University-backed EAT-Lancet report and its ‘planetary health diet’ was finally released to the public, it landed with a thud.

To address the challenges of food security, nutrition, and sustainability, the report’s authors—prominent researchers from institutions across the globe—called for big changes. Britons were urged to cut their beef intake to one burger every two weeks. Much of the western hemisphere was urged to rely more on plant-based foods.

There were criticisms: The report omitted the role food technology companies might have in building a sustainable future. And scientists have questioned whether, if followed, the dietary guidelines would actually make food unaffordable for more than 1 billion people.

Amidst all the discussion, though, one subset of people was especially vocal: meat eaters.

According to an analysis by researchers at Stockholm University and published in The Lancet, a group of meat-eating proponents started the hashtag #yes2meat up to a week before the report was published on January 17, 2019. Many of those responses were critical of the report, and some of them were defamatory, according to the researchers. (The group includes Victor Galaz, deputy director at the Stockholm Resilience Centre, which is a scientific partner of the EAT Foundation—though the researchers state they were not funded by EAT.) Some of the negative posts accused the EAT-Lancet report of being part of a larger vegan agenda. Others went straight for the report’s lead author, Harvard professor Walter Willett, accusing him of having conflicts of interest.

By analyzing Twitter data encompassing 4,278 users and 8.5 million tweets, the researchers dissected how the movement built steam and shaped discussion of the report. “By actively promoting #yes2meat right before, during, and after the EAT-Lancet Commission launch, this counter movement was approximately ten times more likely to be negative about the Commission than positive or neutral,” the researchers wrote.

Most of the interactions were by actual skeptical humans, as opposed to bots, according to the analysis. Among the critics were proponents of the fat-heavy keto diet and the Nutrition Coalition, a group affiliated with Nina Teicholz, an author who has criticized nutrition movements that suggest eating less meat.

That kind of infighting isn’t new, and it isn’t over either. In September, a study published in the Annals of Internal Medicine suggested the health benefits of cutting out meat were minimal, sparking a fierce rebuke from Willett’s colleagues at the Harvard T.H. Chan School of Public Health. Those findings, too, have been accused of falling prey to the influence of corporate funding.

This new analysis shows that social media can have a significant effect on public perception of these scientific spats. Ostensibly, there were three groups of people chattering online about the report: those promoting it, those skeptical of it, and a third, ambivalent group that was found to have grown more skeptical over time as more and more interactions about the report were negative. Of the tweets mentioning EAT-Lancet, the researchers found 29% were positive, 32% were negative, and 38% were neutral. The combined audience was about 60 million people.

The finding raises important questions about how to communicate scientific findings in a world increasingly connected by social media. Given the difficulty in designing definitive nutrition studies and tabulating lifetime environmental impacts, the debate over the medical and environmental health of meat consumption is far from over.