The short answer
IARC classifies processed meat as Group 1 and red meat as Group 2A for colorectal cancer. The widely quoted 18 percent is a relative increase applied to a lifetime risk of about 4 percent, which works out to roughly 7 extra cases per 1,000 people. Group 1 describes how confident scientists are, not how dangerous something is compared with tobacco.
IARC classifies processed meat as Group 1, carcinogenic to humans, and red meat as Group 2A, probably carcinogenic to humans, both for colorectal cancer.
Group 1 describes the strength of the evidence, not the size of the risk. IARC says so explicitly: the classifications rank certainty of evidence, not level of danger.
The headline figure is that each 50 g of processed meat eaten daily raises colorectal cancer risk by about 18 percent. That is a relative increase.
In absolute terms: about 3.9 percent of people in the US are diagnosed with colorectal cancer at some point. An 18 percent relative increase moves that to roughly 4.6 percent, or about 7 extra cases per 1,000 people.
Watch: Processed meat and cancer
55 sec · Captioned · The processed meat link is real — and the risk size surprises people.
Educational only — this video explains general report language and is not medical advice. Only your care team can say what a result means for you.
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The full explanation.
Start with the number that was left out
You have probably seen the headline: processed meat raises colorectal cancer risk by 18 percent. That figure is real, and it is almost always reported without the thing that makes it meaningful.
Eighteen percent is a relative increase, and it applies to each 50 g of processed meat eaten every day. Fifty grams is roughly two rashers of bacon or one hot dog, daily, for years.
Here is the same fact in absolute terms. In the US, about 3.9 percent of people are diagnosed with colorectal cancer at some point in their lives. That is the SEER figure. Raising that by 18 percent gives roughly 4.6 percent. The difference is about seven extra cases per 1,000 people over a lifetime, for the group eating that much processed meat daily. Real, worth knowing, and a very different impression from what the headline creates.
What IARC actually decided
In 2015, an IARC working group classified processed meat as Group 1, carcinogenic to humans, based on sufficient evidence that it causes colorectal cancer. It classified red meat as Group 2A, probably carcinogenic to humans, based on limited evidence. For red meat, IARC noted that if the association proves causal, each 100 g eaten daily would raise colorectal cancer risk by about 17 percent.
Processed meat means meat transformed by salting, curing, fermentation, smoking or similar processes: bacon, ham, sausages, hot dogs, salami, corned beef, jerky. Red meat means all mammalian muscle meat, including beef, veal, pork, lamb, mutton, horse and goat.
Why Group 1 does not mean "as bad as tobacco"
This is the single most misread thing about the classification, and IARC addressed it directly. The Group labels describe the strength of the scientific evidence that an agent can cause cancer, rather than assessing the level of risk. Being in Group 1 alongside tobacco and asbestos means the evidence is equally settled, not that the danger is equal.
The numbers show the gap. IARC cites a Global Burden of Disease Project estimate that about 34,000 cancer deaths worldwide each year are attributable to diets high in processed meat. Tobacco's toll is on a completely different scale. One of IARC's own scientists put it plainly at the time: for an individual, the risk of colorectal cancer from eating processed meat remains small, but it increases with the amount eaten.
Is there an amount that is fine?
IARC concluded that the evidence did not permit a conclusion about whether a safe level exists. What it could say is that risk rises with the amount consumed.
WCRF and AICR turn that into something you can act on. Their recommendation is to consume very little, if any, processed meat, and to limit red meat to no more than about three portions a week, roughly 350 to 500 g of cooked weight. They grade the evidence as convincing that processed meat causes colorectal cancer, and as probable for red meat.
That is guidance about a pattern held over years. It is not a verdict on a bacon sandwich, and it is not a reason to feel that a single meal has done damage.
Where this fits in the bigger picture
If colorectal cancer is what worries you, the thing that moves the needle most is not on your plate. It is screening. Colonoscopy and stool-based tests find and remove polyps before they become cancer, which is a form of prevention that diet cannot match. Ask your clinician when you should start based on your age and family history, and which test suits you.
After that, the well-supported contributors are physical activity, body weight, alcohol and smoking. Cutting processed meat is a reasonable and low-cost change to make. It works best as one item on that list rather than the whole list.
Practical substitutions
If you want to shift without feeling deprived: move processed meat from daily to occasional rather than trying to eliminate it outright, use poultry, fish, eggs, beans and lentils in the places where bacon and deli meat currently sit, and build meals around whole grains, vegetables and pulses, which have their own evidence for lower colorectal risk. Gradual and sustainable beats strict and abandoned.
Sources
Words to know
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Common questions
Is a bacon sandwich really as dangerous as smoking?
No, and IARC has said as much. Processed meat and tobacco are both in Group 1 because the evidence that each can cause cancer is strong. The amount of cancer each causes is entirely different. The Global Burden of Disease Project estimate that IARC cites attributes about 34,000 cancer deaths a year worldwide to high processed meat intake, which is a small fraction of the toll from tobacco. The shared label reflects shared certainty, not shared magnitude.
What counts as processed meat?
IARC defines it as meat transformed through salting, curing, fermentation, smoking or other processes to enhance flavor or improve preservation. That covers bacon, ham, sausages, hot dogs, salami, corned beef, jerky, and canned or preserved meats. Fresh minced beef is not processed meat. Red meat means all mammalian muscle meat: beef, veal, pork, lamb, mutton, horse and goat.
Is there a safe amount?
IARC concluded the evidence did not allow it to say whether a safe level exists, only that risk rises with the amount eaten. WCRF and AICR translate that into practical advice: very little processed meat, if any, and about three portions of red meat a week, roughly 350 to 500 g cooked weight. That is guidance about a pattern over years, not a rule about a single meal.
If I cut out processed meat, is my colorectal risk handled?
It is one contributor among several. Getting screened on schedule does far more for colorectal cancer outcomes than any dietary change, because screening finds and removes polyps before they become cancer. Physical activity, body weight, alcohol, smoking and family history all matter too. Diet is worth attention, but it should not crowd out the colonoscopy or stool test.
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Written by: Cancer ExplainedSources last checked: 2026-07-30 what this meansLast updated: 2026-08-18Next planned review: 2027-07-30
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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