Confusion surrounding nutrition science is nothing new, and this study is yet another example. So it's no wonder that this has generated some buzz in the media. But is it really worth reconsidering the current guidelines to cut back on red and processed meats? Here's our summary of the findings and the criticism, our take (spoiler: we're not convinced), and all the info you need to make informed dietary decisions.
Earlier this month, researchers from NutriRECS published four systematic reviews (a summary of findings from multiple studies) examining the relationship between (a) red and processed meat consumption and (b) chronic disease (ex. diabetes, cardiovascular disease). Their reviews were completed without outside funding (see: no conflict of interest), and were published along with their new "guidelines."
And as we mentioned above, these guidelines were to maintain the status quo of high red and processed meat consumption, contradicting recent recommendations to make efforts to lower the intake of both.
They concluded that the data from the large cohort studies and relatively limited number of randomized controlled trials was "weak, low certainty evidence." In other words, most of the evidence we have connecting meat intake with chronic disease is observational, not experimental. Because of this, it's harder to prove one causes the other.
2) People’s values surrounding how/whether they include red or processed meat in their diets
Their review found that a majority of people who ate meat enjoyed doing so, considered it an important part of their diet, and felt unable to prepare satisfying meals that didn’t contain meat.
3) The actual impact of reducing red and/or processed meat intake on the risk of chronic disease
The panel concluded that although the research does point to benefits of reducing intake to around 1 serving per week, the quality of the evidence is "poor" (see #1), the size of the benefit is small, and ultimately, it's too big an ask for people who feel strongly about eating meat.
One of the reasons for this contradiction was the rating tool the researchers used, called the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Because, although the GRADE criteria were indeed created to assess the quality of evidence in research, they were developed mainly to assess the strength of evidence for drug trials! And unlike drugs, it's nearly impossible to create long-term clinical trials to test the effects of a specific food on health.
So it's no wonder that, when the researchers used a tool meant for drug research on food research, the GRADE criteria resulted in a lower evidence score. And the fact that the researchers chose to use this tool does in fact appear to be relevant—similar reviews which used rating scales designed for foods determined the evidence to be stronger than these researchers did.
The authors’ decision to consider people's taste preferences and willingness to change dietary habits was another point of criticism. We believe that preferences are important to consider on an individual level, but doing so when developing dietary guidelines is questionable.
In all fairness, Dr. Johnson’s work with industry was done outside of the mandatory disclosure period, and the relationship with Texas A&M was formed after the studies were completed. But for an organization that heavily touts its lack of conflicts, it’s surprising to see these undisclosed ties.
The longer answer is that we base our recommendations on reviews of the literature done by our team of nutrition and exercise scientists, who take into account a wide breadth of research. We are not often swayed by the results of one study or group of researchers. We take the broader research landscape into account, and consider the evidence from multiple sources before we come to any conclusions on a recommendation.
Ultimately, it seems that we're in good company in this decision. Since it’s been published, the NutriRECS guideline has come under fire from experts at The Harvard School of Public Health and has prompted both the American Heart Association and the American Cancer Society to issue press releases reiterating their advice to reduce red and processed meat intake. The vast majority of the evidence suggests that reducing intake of red and processed meat improves health outcomes, and that’s what we will continue to recommend.
*In certain cases, we do recommend up to 2 servings of red meat per week to improve iron biomarkers.