Sugary soda and other sweet treats are likely not the only foods to blame for the surge in diabetes across the U.S. New research out of Harvard University supports the theory that regular red meat consumption increases the risk of getting type 2 diabetes.
An average of just one 85-gram (three-ounce) serving of unprocessed red meat—such as a medium hamburger or a small pork chop—per day increased by 12 percent the chances a person would get type 2 diabetes over the course of a decade or two. And if the meat was processed—such as a hot dog or two slices of bacon—the risk increased to 32 percent, even though serving sizes were smaller.
The new study, published online August 10 in the American Journal of Clinical Nutrition, is not the first to find the link between red meat and diabetes risk. But it is the largest and one of the first to look separately at unprocessed and processed meats.
"On a gram-per-gram basis, unprocessed red meat is still better," says Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health and co-author of the new paper. "But unprocessed red meat is still associated with a significantly increased risk."
More than 8.5 percent of U.S. adults have been diagnosed with diabetes, and in some counties in the so-called "diabetes belt" in the South, the numbers exceed 11.2 percent. The rates are expected to keep climbing in the coming years.
Hu suggests that based on the analysis there is indeed a "disease burden that can be attributed to consumption of either processed or unprocessed red meat."
It's what's for dinner, for many
A U.S. adult consumes an average of more than 45 kilograms (100 pounds) of red meat a year. "There's no question that consumption of red meat is too high," Hu says, suggesting nuts, whole grains and low-fat dairy products as healthier alternatives. And diabetes is not the only reason to switch to lighter forms of protein. People who ate 113 grams (four ounces) of red meat a day are more likely to die from any cause over 10 years, according to a 2009 Archives of Internal Medicine study of half of a million people.
Of course, eating red meat for a week "is not going to give someone diabetes—we're talking about habitual consumption," Hu says. And for those uncertain about trading in a filet mignon for a fistful of almonds, the researchers behind the new paper also list poultry and fish as alternatives, although Hu cautions that other research also supports the move to a more plant-based diet.
"It really confirms what other studies have suggested," says Elizabeth Seaquist, director of the Center for Diabetes Research at the University of Minnesota, who was not involved in the new study. The new report analyzed health and dietary information from three large-scale cohort studies (the "Health Professionals Follow-Up Study," and the "Nurses' Health Study I and II"), which encompassed some 200,000 adults. It combined that data with previous studies for a meta-analysis that covered a total of 440,000 men and women who were followed for 10 years or more.
Seaquist puts great confidence in the findings based on the study's sample size, but notes that as an epidemiological study like this one should, it "raises more hypotheses than gives us answers."
The additional incriminating evidence for this category of food seems to swing the pendulum away from refined carbohydrates as the only culprits in advancing diabetes. And the new paper "will heighten awareness of the potential for different dietary components to contribute to diabetes," Charles Burant, director of the Metabolomics and Obesity Center at the University of Michigan Medical School, who also was not involved in the new paper.
For people who have been following the research, however, "the findings are not particularly surprising," Hu says. In fact, despite the big play that sugars and other highly processed carbohydrates have gotten, red meat is actually "one of the most well-established dietary risk factors," he notes.
One of the tricky aspects of lifestyle studies like this one is that unhealthful behaviors often go together, making it tough to tease them apart to see if one is having a larger effect than others. And in the studies, those who reported eating the most red meat also tended to have other risk factors for diabetes, such has having a higher body mass index (BMI), smoking and not getting much physical activity. "People who eat a lot of meats tend to gain more weight," Hu says.
So the new findings might be more "a reflection of poor dietary intake by people who eat meat," Burant says. Seaquist explains more plainly that perhaps "people who eat red meat end up eating French fries with it."