Cut the Bologna: Understanding the WHO's Classification and What it Means for Your Sandwich

Think back to 2015: the Apple Watch was released, Adele released “Hello”, water was discovered on Mars, and Hamilton opened on Broadway.

Do you also remember this headline: “Processed meats rank alongside smoking as cancer causes”? The World Health Organization (WHO) classified processed meats as a Group 1 carcinogen, meaning there was enough strong evidence to say that processed meats were a cause of cancer. And Group 1: as strong of a ranking as tobacco and cancer.

Cue panic.

Bacon was out. Sayonara sausage. Buh-bye beef jerky. And the hot dog eating competition? That was so 2014.

What the WHO actually said

The International Agency for Research on Cancer (IARC) had reviewed a bevy of studies around diet and health, and concluded that “eating processed meat causes colorectal cancer”. Fast forward to March of 2025 - 10 years after the WHO’s warning and some fear that the train has left the station. Colorectal cancer rates are on the rise, particularly in young people.

But why does a processed piece of lunch meat get the axe while baked chicken breast is fine? It comes down to what happens when meat is exposed to dietary nitrates or nitrites, regardless of whether they’re from additive sources or natural sources (like celery salt). The nitrates and nitrites interact with the proteins of the meat and form nitrosamines, which when exposed to the lining of the colon, can trigger good cells to go bad.

Wait, what about historical diets?

When we look at historical diets around the world, including those of some of the healthiest societies, they include processed meats. Looking at it logically, meats had to be preserved in some way before invention of refrigeration. They were likely teeming with nitrosamines. Why weren’t all young people suffering from colon cancer back in the day?

Life before refrigeration also meant life before excessive processing of foods. The foods being eaten with the processed meats were whole, alive, and diverse (think fruits, vegetables, whole grains, nuts, seeds, and beans). These foods fed healthy gut bacteria, promoted good movement of digestion, and provided ample anti-cancer compounds. A cured meat was being eaten aside a handful of nuts, bowl of snap peas, fresh pear, or a snack of olives, and chased by a wedge of seedy, nutty, ancient grain bread.

The Movement factor

Also consider how active people likely were during this time. Their daily movement far rivaled ours - and there were no gyms to speak of. They moved and lifted and ran as their day took them. And if you’ve ever started a regular exercise routine, you may have noticed: regular exercise improves digestion through gut movement.

Why fiber and transit time matter

Pairing a naturally high fiber diet with daily physical activity leads to those carcinogenic compounds having minimal contact time with the colon. And minimal contact time matters. If you love jargon, here you go:

“High NOC concentrations were associated with longer transit time and lower fecal weight, suggesting more efficient microbiota mediated formation and accumulation of these compounds in feces. In contrast, a higher intake of dietary fiber can increase stool volume and shorten transit time, leading to lower NOC concentrations and decreasing their interactions with the colon mucosa” (Ruiz-Saavedra, et al., 2024).

Translation: fiber is protective. It speeds up digestion, gives necessary bulk to stool, cuts down on N-nitroso compounds (a body’s natural creation of these risky molecules), and minimizes how much exposure the colon has to these risky guys.

So, what now?

Sometimes, at this point, my mind starts swimming. I think back to all of the barbecues I’ve been to, cold cut sandwiches I’ve packed for lunch, and jerky sticks I’ve eaten on hikes. I’m doomed. Also, I love a charcuterie board. How am I supposed to go on without a BLT? Forget it. I don’t care.

But I do care. I care a lot. And it doesn’t have to be that hard. I think back to my common sense. Real foods. Balanced diet. Physical activity. Regular digestion. The sandwich isn't operating in a vacuum. It's part of a whole pattern of eating, moving, and living. Focus on the fiber, keep moving, and remember that health is built on the sum of our habits, not one ingredient. And of course, get screened for cancers as recommended by your medical provider.

TL;DR

Processed meats are a cause of increased colon cancer rates, but considering the historical context of a nourishing diet and active lifestyle, all foods can fit in a healthy diet. Get screened.