Eating red meat increases the risk of premature death, according to a new study, which also finds consuming processed meats presents an even greater risk.
The study tracked 120,000 Americans for up to 28 years, using data from two huge, ongoing studies of nurses and other health professionals. Their health is monitored and correlated with their living habits - including their diet.
"So, both processed and unprocessed red meat [were] associated with substantially increased risk of mortality," says Frank Hu of the Harvard School of Public Health, the study's senior author. "And clearly the risk associated with processed red meat is much higher than that for unprocessed red meat."
The researchers concluded that adding one 85-gram serving per day of unprocessed red meat, such as steak or hamburger, raised the risk of premature death by 13 percent.
Switch to a daily serving of processed meat - just two pieces of bacon or 28 grams of sausage, for example - and the risk goes up 20 percent.
In particular, eating red meat was linked to higher risk of death from cardiovascular disease and from cancer.
The study also found that substituting other foods for red meat - such as fish, poultry, and whole grains - could substantially cut the risk of premature death.
Although the study tracked participants for more than two decades in many cases, Hu says the impact of a change in diet can often be seen much sooner.
"In most situations, dietary factors have immediate and short-term effects on cardiovascular risk factors and type 2 diabetes," Hu said. "So I don't think you have to wait for 20 years for the increased risk to occur."
The meat industry is taking issue with the findings.
Betsy Booren, director of Scientific Affairs for the American Meat Institute Foundation, criticizes the study's methodology, which included asking participants to remember how much meat they ate in the past.
Booren also points out that eating habits are only one of a number of factors that can affect disease and death.
"Many chronic diseases - cardiovascular disease, diabetes, cancer - the main risk factors are not food products," she says. "It's obesity, being overweight, and your genetics."
Hu's study did include a statistical adjustment for obesity and family history of disease, plus smoking, and found that red meat still contributed to premature death and disease.
Hu says his study doesn't mean that everyone should become a vegetarian, but that choosing alternative sources of protein may be a good idea.
"We found that other sources of protein, such as fish, poultry, nuts, legumes, and no-fat dairy products can have substantial benefits if they are used to replace red meat."