ther study author, Emanuele Di Angelantonio of the University of Cambridge, says the main problem is that the paper was "wrongly interpreted by the media." "We are not saying the guidelines are wrong and people can eat as much saturated fat as they want. We are saying that there is no strong support for the guidelines and we need more good trials."
Willett says correcting the paper isn't enough. "It is good that they fixed it for the record, but it has caused massive confusion and the public hasn't heard about the correction." The paper should be withdrawn, he argues.
The controversy should serve as a warning about meta-analyses, Willett adds. Such studies compile the data from many individual studies to get a clearer result. "It looks like a sweeping summary of all the data, so it gets a lot of attention," Willett says. "But these days meta-analyses are often done by people who are not familiar with a field, who don't have the primary data or don't make the effort to get it." And while drug trials are often very similar in design, making it easy to combine their results, nutritional studies vary widely in the way they are set up. "Often the strengths and weaknesses of individual studies get lost," Willett says. "It's dangerous."