The World Health Organization’s cancer research arm Monday declared processed meat a carcinogen and said red meat is probably one, too.

Here’s what experts have to say about what this new warning means for your diet:

Q: What meats are they talking about exactly?

A: The International Agency for Research on Cancer’s definitions of processed meat and red meat are very wide. Processed meats encompass any meats that have been “transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.” This would include sausages, corned beef, hot dogs, beef jerky, canned meat, meat-based preparations and sauces, turkey and chicken cold cuts, as well as bacon.

Red meat refers to “all types of mammalian muscle meat,” such as beef, veal, pork, lamb, mutton, horse – even goat.

Q: What kind of cancers did the scientists look at?

A: For processed meat, the carcinogen label was given based on studies about colorectal cancer. They also found an association between processed meat and stomach cancer. For red meat, the data pointed to associations with colorectal, pancreatic and prostate cancers.

Q: Why do they think these are dangerous?

A: Scientists think that something bad happens to meat during the process of salting, curing or other treatment that causes the buildup of carcinogenic chemicals such as N-nitroso-compounds and polycyclic aromatic hydrocarbons in the food. In red meat, cooking can also produce suspected carcinogens – in this case heterocyclic aromatic amines and polycyclic aromatic hydrocarbons. The IARC report, published in Lancet Oncology, notes that “high-temperature cooking by pan-frying, grilling or barbecuing generally produces the highest amounts of these chemicals.”

Q: What’s the distinction between the classification that the IARC gave to processed meat vs. red meat?

A: The group put processed meat products into its highest risk category meaning that they believe there’s pretty strong evidence to back up this link. It’s the same designation that has been given to really serious cancer-causing agents, such as air pollution and different types of radiation.

Red meat was put into the second highest category of being a “probable” carcinogen, meaning that there’s limited evidence of the link in humans but a lot of evidence in experimental animals.

Q: Uh-oh. I eat a lot of meat. What do I do now?

A: The IARC’s director, Christopher Wild, said that the group’s findings support recommendations to “limit” intake of meat. But Wild also hedged a bit, saying that red meat has “nutritional value.”

The American Cancer Society’s Susan Gapsur recommends that people who do eat meat begin to cut back on the amount of red meat they consume and “really limit” their intake of processed meat. Gapsur, a vice president for epidemiology, said people should be moving toward a more plant-based diet and choose fruits, vegetables, and beans as alternatives to meat.

Marion Nestle, a professor of nutrition, food studies and public health at New York University, said her recommendation on processed meat and red meat is the same: Eat less. But Nestle stops short of recommending everyone should become a vegetarian.

“Some people are interpreting it as don’t eat meat at all. I don’t know if that’s reasonable,” she said. “The evidence against processed meat is very strong, but it’s very hard to consider giving up. A BLT is really a wonderful thing.”

Q: That’s helpful, but what I really need to know is the bottom line. What’s a safe level of meat consumption? Is it OK for me to eat a hamburger with bacon twice a week? Once a week? Once a month?

A: While scientists have come up with that sort of general recommendation for alcohol consumption (one drink a day), none exists for meat. A person’s individual biology is complex and a safe level for one person may not be safe for another. It depends on what the rest of your diet looks like, how often you exercise, your genes and a whole slew of other factors.

U.S. dietary guidelines recommend that Americans eat diets rich in fruits and vegetables, whole grains, seafood, legumes and dairy and stay away from red meat but they don’t offer any specific numbers. The World Cancer Research Fund International comes the closest – suggesting that people who eat red meat consume less than 500 grams (18 oz.) a week and very little if any processed meat.

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.