The International Agency for Research on Cancer (IARC) has classified processed meat as a carcinogen, something that causes cancer. And it has classified red meat as a probable carcinogen, something that probably causes cancer. IARC is the cancer agency of the World Health Organization.

Processed meat includes hot dogs, ham, bacon, sausage, and some deli meats. It refers to meat that has been treated in some way to preserve or flavor it. Processes include salting, curing, fermenting, and smoking. Red meat includes beef, pork, lamb, and goat.

Twenty-two experts from 10 countries reviewed more than 800 studies to reach their conclusions. They found that eating 50 grams of processed meat every day increased the risk of colorectal cancer by 18%. That’s the equivalent of about 4 strips of bacon or 1 hot dog. For red meat, there was evidence of increased risk of colorectal, pancreatic, and prostate cancer.

Overall, the lifetime risk of someone developing colon cancer is 5%. To put the numbers into perspective, the increased risk from eating the amount of processed meat in the study would raise average lifetime risk to almost 6%.

Colleen Doyle, MS, RD, American Cancer Society managing director of nutrition and physical activity, says, "We should be limiting red and processed meat to help reduce colon cancer risk, and possibly, the risk of other cancers. The occasional hot dog or hamburger is okay."

The American Cancer Society has long recommended a diet that limits processed meat and red meat, and that is high in vegetables, fruits, and whole grains. The American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention recommend choosing fish, poultry, or beans instead of red meat and processed meat.

Avoiding tobacco, getting to and staying at a healthy weight, getting regular physical activity, and limiting alcohol can also help people lower their risk of getting many types of cancer.

IARC published its report online October 26, 2015 in The Lancet Oncology.