Eat More - Or Less - Meat?
The question of whether or not it’s healthy to cut back on eating red and processed meat seemed settled years ago. The American Cancer Society, the American Heart Association and the U.S. Dietary Guidelines have all recommended limiting consumption of these foods. The World Health Organization’s International Agency for Research on Cancer has classified processed meat products as carcinogens (these include hot dogs, ham, bacon, sausage and some deli meats).
In October (2019) our long-standing views about meat consumption were challenged by widely publicized research concluding that eating red and processed meats isn’t so bad for human health. An international team, led by Bradley Johnston Ph.D. of Canada’s Dalhousie University, reported after reviewing more than 200 studies on the subject that cutting back on the amount of meat you eat would have “little to no effect” on your risk of diabetes, cancer and heart disease. The researchers reported that reducing consumption of unprocessed red meat would cut deaths from heart disease by only four individuals per 1,000 persons over 10.8 years, deaths from type 2 diabetes by six people per 1,000 over 10.8 years and 7 people per 1,000 over a lifetime. Similar results were seen for reducing consumption of processed meat.
Most meat lovers may look at those numbers and conclude that there’s no point in reducing the amount of meat they eat. But critics of the analysis (and there are many!) argue that it didn’t succeed in making the case that it’s okay to ignore long-standing recommendations to limit meat consumption. A statement from the Harvard T.H. Chan School of Public Health maintains that the new guidelines “are not justified, as they contradict the evidence generated” by the researchers’ own meta-analyses. Among the five published reviews, the Harvard statement noted that three “basically confirmed previous findings on red meat and negative health effects.”
Frank Hu, M.D., Ph.D., chair of the Department of Nutrition at Harvard, noted that earlier studies have shown that a diet low in red and processed meat is associated with a 14 percent lower risk of death from cardiovascular disease, an 11 percent lower risk of death from cancer, and a 24 percent lower risk of type 2 diabetes.
Taking estimates of current red and processed meat consumption into account, Dr. Hu said that a moderate reduction could cut deaths by about 200,000 persons per year. “Even if only half of the reduction is real, that’s still of huge public health significance,” he added.
In her online column “Food Politics,” Marion Nestle, M.P.H., Ph.D., emerita professor of Nutrition, Food Studies and Public Health at New York University, wrote that, “Common sense is what’s missing in these studies. Do the authors really believe that:
- Meat eaters are healthier than vegetarians?
- Eating more meat is better for health?
- Meat eaters are less obese and have less heart disease and cancer than those who eat less?”
If not, she added, “the conclusions make no sense.”
Part of the problem here is the difficulty of performing nutrition studies. As you may know, the most respected research comes from randomly controlled, blinded trials where, for instance, if you want to know whether a new drug works, you assemble a group of patients, some of whom take the drug while others get a placebo. Neither the patients nor the researchers know who received the real thing until results are analyzed when the study ends. That kind of study isn’t feasible when you’re trying to determine whether nutritional changes have an effect on health. The Harvard statement noted that there never has been a randomized controlled trial looking at long-term health effects stemming from reducing red meat consumption due to “practical and ethical reasons.” The authors of the new investigation emphasized the same point.
In most nutritional studies, researchers collect dietary information from volunteers, then check on their health in subsequent years. While this may sound simple, researchers can’t document everything the volunteers eat or what changes they make in their diets – or lifestyles – over time.
There are other consequences of eating meat to consider beyond its effect on individual health. The slaughter of billions of animals annually for use as human food has been a long-standing concern among vegetarians. (You can find a chilling continuous count of the numbers of animals killed for food at The Animal Clock). The toll is appalling considering that we don’t need to eat animals in order to survive – we can get along very well on diets that are plant-based.
Beyond that is the impact of the consumption of meat and dairy products on the environment. In a study published in June 2018, researchers at the UK’s University of Oxford reported that by giving up these products, individuals in the UK could reduce their carbon footprint from food by up to 73 percent, and if everyone followed a vegan diet, worldwide farmland use could be reduced by 75 percent.
This would lead to a significant drop in greenhouse gas emissions and free up wild land lost to agriculture, which the study identified as one of the primary causes of mass wildlife extinction. The investigators also reported that production of meat and dairy products is responsible for 60 percent of greenhouse gas emissions but provides only 18 percent of calories and 37 percent of protein levels worldwide.
Bradley C. Johnston et al., “Unprocessed Red Meat and Processed Meat Consumption: Dietary Guideline Recommendations From the Nutritional Recommendations (NutriRECS) Consortium,” Annals of Internal Medicine, October 1, 2019, DOI: 10.7326/M19-1621