By Robert Bazell
NBC News
It is far from a shocking revelation that red meat is not health food. But a new study from the highly respected researchers at the Harvard School of Public Health offers some of the best and most detailed evidence yet that a daily serving of meat can increase risk of heart disease or cancer.
The Harvard scientists followed almost 84,000 women and 38,000 men in the Nurse’s Health Study and Health Professional’s Follow-Up Study for 28 years. It found those eating a daily serving of red meat were 13 percent more likely to die in the study period, and approximately 14 percent more likely to develop heart disease or cancer. Those numbers go up to 20 percent more deaths and an estimated 18 percent more heart problems and cancer for those who reported eating a daily serving of processed meats such as hot dogs, salami and bacon.
In the realm of health risks, these are not huge numbers. Daily cigarette smoking adds risk of some 2,000 to 4000 percent for these hazards. But across the U.S. population, Americans love of meat likely accounts for about 1.5 million excess deaths every decade, according to research from the National Institutes of Health.
According to the American Meat Institute, Americans consume on average 65 pounds of pork and a similar amount of beef per person every year. Those numbers have changed little over the past two decades. At the same time, chicken consumption has climbed sharply to around 80 pounds a year, while turkey logs in at 15 pounds a year. We’re eating more birds, but no fewer mammals.
The Harvard research is very credible, even though it is a so-called “observational” study. The highest level of proof is a “controlled trial” where half the people would eat meat and the other would not. That’s obviously not practical for multi-decade dietary study. The Harvard researchers have a long track record with their observations of nurses, doctors, and other health professionals. Blood tests confirm that what people report as their diet tends to be accurate -- as are their health records.
In addition, these results neatly coincide with a decade long study published in 2009 of more than 500,000 people from the National Cancer Institute. That confirmation strengthens the argument enormously.
In an editorial in the same issue of the Archives of Internal Medicine with the Harvard study, Dr. Dean Ornish, the preventive medicine guru of the San Francisco Bay area, points out that red meat is harmful not just to our bodies, but also to the planet. It takes enormous amounts of plants, requiring energy-intensive fertilizers, to fatten cattle and pigs. Ornish cites a study finding that the amount of energy required to produce a Quarter Pounder with Cheese equals burning 7 pounds of coal.
Ornish -- who once opposed most fat in the diet -- now agrees with the Harvard group that there are “good fats,” such as fish oil and vegetable oils and “bad fats,” including the saturated fats found in meat and the industrially created trans fats. Ornish concludes there is an emerging consensus of what constitutes a healthy diet: little or no red meat; more “good carbs,” such as those in fruits vegetables and whole grains; fewer “bad carbs,” such as refined sugar, high-fructose corn syrup and white flour; more good fats and fewer bad fats. And to the extent possible, we should eat less of everything, especially junk food.
Those conclusions, the product of decades of many big research projects, will likely stand for a long time. So, we know what a healthy diet is. The question is: Will our taste buds and will power allow us to stay with it?
Bon appétit.
Robert Bazell is NBC's chief science and medical correspondent. Follow him on Facebook and on Twitter @RobertBazellNBC
Related story: