Dr. Laine noted that people on both sides of the meat issue have conflicts of interest. “Many of the people who are criticizing these articles have lots of conflicts of interest they aren’t talking about,” she said. “They do workshops on plant-based diets, do retreats on wellness and write books on plant-based diets. There are conflicts on both sides.”

Dr. Laine said if Dr. Johnston had chosen to disclose a financial relationship with the food industry group, it would not have changed the journal’s decision to publish the research. What matters to the journal editors and peer-review team, she said, is the fact that the group had clear protocols for examining the data and was transparent about its methods.

“I don’t think we would have made a different decision about publishing the manuscript if he had that on his conflicts disclosure,” said Dr. Laine. “We certainly know that in the past he did nutrition research that was funded by industry. It’s a judgment call if that should be disclosed. I think at some level that’s a little bit of noise around this. The methods of what these researchers did and their conclusions are out there, and people can disagree with that.”

Dr. Gordon Guyatt, chair of the 14-member panel that reviewed the analysis, said he is confident that the work was not in any way influenced by industry.



"Perhaps Brad was a little naïve, and both I and perhaps Christine Laine were a little negligent in it not occurring to us that he should probably declare the previous money he got from the previous project,” said Dr. Guyatt, an internal medicine physician and a distinguished professor at McMaster University. “All of that being said, I feel personally extremely comfortable that it had no effect on what we did.”

Dr. Guyatt noted that for 20 years he has been a pescatarian who eats only fish and no other meat. “Before I was involved in these systematic reviews and looking carefully at evidence, I had three reasons for not eating meat — animal welfare, the environment and health. Now I only have two reasons for not eating meat.”

Critics of the meat study say that it has similarities to the industry-funded sugar study and uses the same standard to evaluate evidence. Dr. Frank Hu , the chair of the nutrition department at the Harvard T.H. Chan School of Public Health, said he was stunned when he realized that Dr. Johnston was both the leader of the meat study and the same researcher who led the industry-funded review that attacked guidelines advising people to eat less sugar. He said that in both cases Dr. Johnston undercut sugar and meat recommendations by using a tool called GRADE that was mainly designed to rate clinical drug trials, not dietary studies.

“You can’t do a double-blinded placebo-controlled trial of red meat and other foods on heart attacks or cancer,” Dr. Hu said. “For dietary and lifestyle factors, it’s impossible to use the same standards for drug trials.”