“Men and women with higher intake of red meat were less likely to be physically active and were more likely to be current smokers, to drink alcohol, and to have a higher body mass index. In addition, a higher red meat intake was associated with a higher intake of total energy but lower intakes of whole grains, fruits, and vegetables.”
That quote comes directly from the research report from the Harvard School of Public Health, which was widely covered in the consumer media with headlines essentially saying “eating red meat will kill you.”
The study, reported in the journal Archives of Internal Medicine, involved surveys and health tracking of a large number of subjects over a period of 22 years. The researchers found a higher incidence of red-meat consumption among study participants who developed diseases or died during the study period.
The opening quote illustrates a problem with this type of research, especially when researchers, or the media, draw conclusions not supported by the study’s design. The researchers, in this case, concluded greater consumption of red meat is “associated” with higher mortality risk. The media, naturally, interpreted that to mean one thing causes the other and “red meat will kill you.”
I would suggest that in reality, the study shows an "association" between people’s overall lifestyles and their level of red-meat consumption.
Let’s imagine two test fictional test subjects. We’ll call them Jim and Bob. Both are 45-year-old males with relatively non-physical employment. Both had “slipped” a bit in terms of diet and exercise through their early adulthood, eating unbalanced diets, lots of fast food, maybe drank too much, rarely exercised and gained significant weight.
But at some point, Jim decided to make some changes to improve his health. He began an exercise program and kept at it. He started eating more home-cooked meals including plenty of fresh fruits and vegetables. He made oatmeal for breakfast instead of eggs and bacon. He cut back on his beer consumption and got a better night’s sleep. Popular culture led him to believe (rightly or wrongly) that red meat makes people fat and damages their health, so he substituted more chicken, fish or beans.
Bob, on the other hand, didn’t have the interest or motivation to change. He kept eating a diet high in simple carbohydrates and calories and short on plants. He drank more than he should and smoked more than anyone should. He thought about exercising, but stayed on the couch instead.
At the conclusion of the study, health-conscious Jim is not overweight and is free of heart disease or other problems. Bob, however, is overweight and suffering from diabetes and/or heart disease.
So did the red meat cause Bob’s disease? Did avoiding red meat cause Jim’s good health? The researchers imply it did, indicating they used statistical tools to isolate one variable from the complex interactions between all the lifestyle variables influencing health.
Betsy Booren, director of scientific affairs for the American Meat Institute Foundation, put it this way:
“Beyond the major weakness of this being an epidemiological study which uses survey data – not test tubes, microscopes or lab measurements--the researchers method of collecting and analyzing their data is highly inaccurate. The information in the report indicates that estimates of red and processed meat intake were only 27 - 35 percent accurate versus actual measurements. The researchers also inserted estimated data where an actual survey measurement was missing and also stopped updating the dietary information once participants reported a diagnosis. All of these factors could have significant impacts on the results.
“Too often, epidemiological findings are reported as ‘case closed’ findings, as if a researcher has discovered the definitive cause of a disease or illness. But epidemiological studies look at a multitude of diet and lifestyle factors in specific volunteer human populations and use sophisticated statistical methods to try and tease out relationships or associations between these factors and certain forms of disease. This method of comparing relationships has many limitations which are widely recognized by researchers in this field. More often than not, epidemiological studies, over time, provide more contradictions than conclusions.
“All of these studies struggle to disentangle other lifestyle and dietary habits from meat and processed meat and admit that they can't do it well enough to use their conclusions to accurately recommend people change their dietary habits. What the total evidence has shown, and what common sense suggests, is that a balanced diet and a healthy body weight are the keys to good health.”
Anyone smell an agenda?
Another highly questionable aspect of this issue, is the “invited commentary” that runs alongside the research report in Archives of Internal Medicine. The commentary, titled “Holy Cow! What's good for you Is good for our planet,” was submitted by Dean Ornish, MD. In it, he cites a wealth of discredited, non-scientific misinformation about the environmental impacts of livestock production. “Many people are surprised to learn that animal agribusiness generates more greenhouse gases than all forms of transportation combined,” he writes. “The livestock sector generates more greenhouse gas emissions than transportation as measured in carbon dioxide equivalent (18 percent versus 13 percent).”
Well, they should be surprised, because it isn’t true. Dr. Ornish pulled his silly statistics from the 2006 report titled Livestock's Long Shadow, from the Food and Agriculture Organization of the United Nations (FAO). The figures used in that report have been soundly discredited, and even the report’s authors admitted their massive errors two years ago. It seems that when the FAO group conducted their “lifecycle analysis” of livestock production they included greenhouse gas emissions from every input and production stage – tillage for feed crops, fertilizer, grain processing, tractor manufacturing, meat processing, you name it. For transportation, they conducted, let’s say, an abbreviated analysis, looking only at tailpipe emissions. Oops. The U.S. environmental protection agency estimates livestock’s contribution to greenhouse gasses at less than 3 percent of the total. Seems a scientist submitting a commentary to a scientific journal would be more concerned with facts.
For perspective on livestock’s environmental impact, read “Fading footpring, shrinking shadow” from Drovers/CattleNetwork.
Personally, I’m going to keep eating fruits and vegetables. I’m going to keep exercising and keep not smoking. I’m going to limit my alcohol intake (although reading some of these things makes me want to reach for the whisky bottle). And I’m going to keep enjoying beef as part of a balanced diet.
Read “Red meat consumption and mortality” from Archives of Internal Medicine.
Read “Holy cow! What's good for you is good for our planet” from Archives of Internal Medicine.