An eagerly awaited report from the World Health Organization (WHO) states that processed meats such as bacon and sausages cause cancer, and red meat likely does so too.

Photo by Benjamin Faust.

The France-based International Agency for Research on Cancer (IARC), part of the WHO, put processed meats on the top of their “things that cause cancer list”, grouping them alongside tobacco, asbestos and diesel fumes, for which there is “sufficient evidence” of cancer links.

“For an individual, the risk of developing colorectal (bowel) cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” Dr Kurt Straif of the IARC said in a statement.

Along the years, there have been many studies that linked processed and red meats with cancer (especially bowel cancer), but there were always some doubts floating about. Now, the 22-member panel analyzed animal experiments, studies of human diet and health, and cell mechanisms that could lead from these meats to cancer.

“These findings further support current public health recommendations to limit intake of meat,” Dr. Christopher Wild, who directs IARC, said in a statement.

The decision wasn’t unanimous though, and a “probably” still crept in to the report. Many studies show the links, both in populations of people and in tests that show how eating these foods can cause cancer, the International Agency for Research on Cancer (IARC) said in its report, released in the Lancet medical journal.

This could give you cancer. Photo by Niklas Rhose.

Most reports on the links between meat and cancer have been softened with some element of doubt, but the IARC uses clear and direct language in saying processed meat causes cancer. There are no phrases such as “may cause” in the report.

“Overall, the Working Group classified consumption of processed meat as ‘carcinogenic to humans’ on the basis of sufficient evidence for colorectal cancer,” the report reads. “Additionally, a positive association with the consumption of processed meat was found for stomach cancer. The Working Group classified consumption of red meat as ‘probably carcinogenic to humans’,” it added.

In case you’re wondering just what processed meat is, the panel also defines it:

“Processed meat refers to meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation. Most processed meats contain pork or beef, but might also contain other red meats, poultry, offal (eg, liver), or meat byproducts such as blood.”

This of course, isn’t exactly news – it’s only a meta-analysis, of things we’ve already known, but it’s a way of the world’s leading health organization to draw its line and tell people to stop eating these foods. But they even put some figures on it:

“The experts concluded that each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18 percent,” the IARC said. “For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” said IARC’s Dr. Kurt Straif.

They also mentioned red meat, which was also documented to favor the development of cancer. Red meat is defined as follows:

“Red meat refers to unprocessed mammalian muscle meat—for example, beef, veal, pork, lamb, mutton, horse, or goat meat—including minced or frozen meat; it is usually consumed cooked,” the IARC said in its report.

Red meat was included in a lower category, which means that while there is evidence for it causing cancer, there is still quite a lot of room for debate. But while processed meat seems to be decidedly bad for your health, not everybody is convinced about red meat.

The $95 billion U.S. beef industry has been preparing a retaliation for months, and they’ve been rallying numerous scientists to their cause – even some unafililiated with the meat industry.

“We simply don’t think the evidence support any causal link between any red meat and any type of cancer,” said Shalene McNeill, executive director of human nutrition at the National Cattlemen’s Beef Association.

For now, the takeaway seems to be this: you need to stop eating processed meat. They have a number of damaging effects, including elevating stroke risk, raising cholesterol and, of course – cancer. If you absolutely can’t give it up, then reduce it. Quantity does matter, and less is, while not ideal, better than more. The same goes for red meat – if you must have it, don’t have it every day. It’s not sustainable, it’s bad for the animals, and it’s bad for you.

We’re getting to a point where science is starting to understand what’s good for us and what’s not. Let’s make the science count, shall we?