It’s a headline you’ve probably seen by now splashed all over the news sites and channels – “Eating More Red Meat Ups Mortality Risk.” (Red meat once again wears the black hat: surprise, surprise.) Actually, millions of readers/viewers have likely stumbled across the caption and unfortunately taken it at face value. But you know us by now. It’s just too much fun being the merry skeptics when it comes to these sound bites of misinformation.
First things first. If you haven’t read about the aforementioned study yet (or want to read the full text for yourself – always advisable), here’s the link to the free full text. The report was published in the March 23rd issue of the Archives of Internal Medicine and has been picked up by just about every major news organization this week. The gist goes something like this: the researchers administered a “Food Frequency Questionnaire” to approximately half a million people (ages 50-71) who were part of the National Institutes of Health-AARP Diet and Health Study. Participants responded to 124 questions regarding specific food and drink intake as well as portion size in the previous twelve months. (The questionnaire (PDF) is an engrossing read in and of itself.) Researchers then followed the group for ten years and recorded mortality statistics.
The results: At the end of the ten year period, 47,976 men and 23,276 women had died. Researchers checked causes of death and overall mortality against reported meat consumption. Their conclusion: “Red and processed meat intakes were associated with modest (my emphasis) increases in total mortality, cancer mortality, and cardiovascular disease mortality.” More specifically, those participants (20%) who consumed the most red meat (median = 62.5 grams per 1000 daily calories) showed slightly greater risk for overall, cardiovascular and cancer death than the 20% who consumed the least (median = 9.8 grams per 1000 daily calories) red meat. The same statistic held for processed meat intake (“most” median = 22.6 grams; “least” median = 1.6 grams). The inverse trend was found for white meat (turkey, chicken and fish): those who ate the most white meat showed less risk for overall, cardiovascular and cancer death (as well as death from other causes) than those who ate the least white meat.
As mentioned, I invite you to read the full study and judge for yourselves. It’s as full of holes as your average Swiss cheese. (Smells like it too.) Where to start? How about the whole self-report questionnaire? All together now: let’s recall what we ate over the last year and summarize it in a few lines… Ah, the broad brush of the observational study…
As for some specific critiques… There is, not surprisingly, no accounting for carb intake in this study. We know (broken record alert) that carbs drive insulin and insulin drives fat production, fat storage, inflammation and coronary heart disease. (Now if only this point would ever get equal time…) Even a moderate carb diet produces enough added insulin to drive production of triglycerides from both the extra carbs and the ingested fats. Maybe all these people ate an average of enough extra carbs that the added fats from the meat contributed more to the slightly higher average build-up of CHD in the highest quintile. (How much of their red meat consumption came in the form of steaks and roasts versus hamburgers with their obligatory buns, etc.?)
Fittingly, a lesser publicized study this week reported that a third of Americans have high triglyceride levels. (Check out our recent post on blood markers for more on the whole lipid picture.) Of course, the researchers and general media are pinning the risk (as always) on saturated fat consumption instead of carbohydrate intake, the true culprit in triglyceride measures. And don’t even get me started on the effects of HFCS on triglycerides.
The establishment never seems to tire of this saturated fat hobby horse, and its treatment of both the triglyceride findings and the meat study further confirm this. (Yes, I’m contending that the meat study is another thinly veiled attempt to “confirm” Conventional Wisdom thinking – conscious or unconscious.) Scientific method, after all, is predicated on hypothesis. Let’s hypothesize the same things over and over again: fat or, in this case, red meat is bad for you. Starting from that mindset, it’s not too surprising that you can “prove” it by loosely correlating/conflating meat intake with mortality. Maybe you can’t and won’t, but your results will likely be influenced by the limitations of your scope, your focus, the assumptions that lead you to discount various factors that have everything to do with your results. I could hypothesize that the air in California is bad for you, and I could bias the study by focusing my analysis in and around Bakersfield and in doing so prove my hypothesis. Or I could focus on the pristine air in Mammoth and get a different result.
What if the hypothesis in this study had been that conventional “CAFO” meat (Concentrated Animal Feeding Operations: hormones, antibiotics, pesticide residue, grain-fed) slightly increases cancer and coronary heart disease? You would then necessarily test standard meats against clean 100% grass-fed/finished, hormone-free, pesticide and antibiotic-free meats, and maybe test them all against a meatless diet. But in this case they didn’t. If they had, I could predict that they would see a measurable difference between those who ate ANY amount of CAFO meat and those who ate only clean meats. There is no separation between the two in this current study – if in fact any of those participating ate any grass-fed clean meat at all. I could conceivably use this study to “prove” my ongoing point that CAFO meats, processed meats, etc are somewhat less healthy…exactly as we say they are in the Primal Blueprint. But then there are so many other confounding factors….
The authors acknowledge that the preparation of meats could be a factor. We know that overcooking meats can produce HCAs (heterocyclic amines), which are carcinogenic, and maillard reactions, which may be atherogenic. At MDA, we suggest that you not routinely overcook meat for these reasons. There is no accounting for the preparation of the meat in this study, except to acknowledge that processed meats may increase risk.
Furthermore, it’s been shown that consumption of vegetables and other antioxidant-rich foods/supplements/drinks (like wine) with meat can neutralize the potential carcinogenic attributes conferred by cooking/overcooking. The highest meat group had the lowest antioxidant intake. Maybe that explains the minor difference – even in the face of all other variables.
Finally, there remains a dizzying (uh, discounting?) array of other variables (on top of the aforementioned variables) put together in one rather telling little package. In the authors’ own words, “Subjects who consumed more red meat tended to be married, more likely of non-Hispanic white ethnicity, more likely a current smoker, have a higher body mass index, and have a higher daily intake of energy, total fat, and saturated fat, and they tended to have lower education and physical activity levels and lower fruit, vegetable, fiber, and vitamin supplement intakes.” Hmmm… This statement seems to say it all (well, almost) if you ask me. The authors ultimately seem pretty good at unraveling their own argument. Too bad most of the media outlets can’t seem to pick up on that point.
For your further reading pleasure, Michael R. Eades, M.D. takes on this latest bunk in his blog by highlighting a few just as timely studies that didn’t get as much press this past week. (Spoiler alert: the studies actually contradict the findings of this observational meat maligning research.) As Dr. Eades suggests, the media has unappreciated power in determining what studies get press and which don’t. Predictably, those that bolster the prevailing mindset tend to get picked up. (The large numbers of subjects inherent in broad observational studies like these also act as bright, shiny enticements, however illusory their results are.)
The real take home message from this study is this: Don’t be obese, do exercise, don’t smoke, eat plenty of vegetables and fruit, take supplements, avoid processed meats, avoid overcooked meats, eat from a variety of animal foods. (And when you eat red meat or any other meat, try to eat the cleanest form possible because it would appear that the hormone-laced, antibiotic-tainted, grain-fed CAFO meat may slightly increase your risk of CHD and cancer – or not.) Red meat itself, at the end of the day, appears to be little more than a red herring.
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending more than three decades educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates flavorful and delicious kitchen staples crafted with premium ingredients like avocado oil. With over 70 condiments, sauces, oils, and dressings in their lineup, Primal Kitchen makes it easy to prep mouthwatering meals that fit into your lifestyle.