Original article from Harvard
A controversial “dietary guidelines recommendation” published in Annals of Internal Medicine suggests that adults can continue to consume red meat and processed meat at current levels of intake. 
This recommendation runs contradictory to the large body of evidence indicating higher consumption of red meat—especially processed red meat—is associated with higher risk of type 2 diabetes, cardiovascular disease, certain types of cancers, and premature death. However, according to the Annals authors, their guidelines were based on a series of “rigorous” systematic reviews (published simultaneously [2-6]) that would presumably account for all this available evidence.
Confused? We asked our experts to take a closer look at the research behind these guidelines. You can find the in-depth analysis below, but here are their key takeaways:
- The new guidelines are not justified as they contradict the evidence generated from their own meta-analyses. Among the five published systematic reviews, three meta-analyses basically confirmed previous findings on red meat and negative health effects.
- The publication of these studies and the meat guidelines in a major medical journal is unfortunate because following the new guidelines may potentially harm individuals’ health, public health, and planetary health. It may also harm the credibility of nutrition science and erode public trust in scientific research. In addition, it may lead to further misuse of systematic reviews and meta-analyses, which could ultimately result in further confusion among the general public and health professionals.
- This is a prime example where one must look beyond the headlines and abstract conclusions. It is important for journalists, health professionals, and researchers to look beyond the sensational headlines and even the abstracts of the papers to verify the evidence behind the claims. It’s also crucial to understand that nutrition research is a long and evolving process, and therefore critical to look at the totality of the evidence.
- These studies should not change current recommendations on healthy and balanced eating patterns for the prevention of chronic diseases. Existing recommendations are based on solid evidence from randomized controlled studies with cardiovascular risk factors as the outcomes, as well as long-term epidemiologic studies with cardiovascular disease, cancer, type 2 diabetes, and mortality as outcomes. To improve both human health and environmental sustainability, it is important to adopt dietary patterns that are high in healthy plant-based foods and relatively low in red and processed meats.
Q&A: Reviewing the scientific process behind the guidelines
Five reviews were published alongside the panel’s guidelines that informed their recommendations, including three meta-analyses. Can you walk us through the findings and your evaluation of the data?
What’s your take on the other two reviews, one of which considered people’s preferences on meat consumption?
It’s interesting that the results from the meta-analyses actually confirm existing findings. So why did the panel issue a recommendation that adults continue their habits, effectively contradicting their own findings and existing guidelines on red meat consumption?
Why would a prestigious medical journal publish dietary guideline recommendations by a self-appointed panel?
In summary, what are the major problems with these new guidelines concerning red and processed meat?
- These guidelines are inconsistent with the principle of “first do no harm.” In clinical practice, it would be irresponsible if a patient who reports eating two servings of red/processed meat daily is told by their doctor not to worry and continue the habit.
- These guidelines are inconsistent with the precautionary principle in public health. From a public health point of view, it is irresponsible and unethical to issue dietary guidelines that are tantamount to promoting meat consumption, even if there is still some uncertainty about the strength of the evidence.
- The panel declared “considerations of environmental impact” out of the scope of their recommendations. This is a missed opportunity because climate change and environmental degradation have serious effects on human health, and thus is important to consider when making recommendations on diet, even if this is addressed separately from direct effects on individual health.