Is red and processed meat really bad for me?
Yes, and this applies above all to processed meat: the association with colorectal cancer and cardiovascular disease is solid enough that eating less of it is a practical step for your health.
Processed meat (sausage, ham, bacon, lardons) has been officially classified by the WHO as carcinogenic to humans. Unprocessed red meat appears on the list of 'probably carcinogenic'. It is important to understand that this says something about the category, not about exactly how large your personal risk is.
The strongest evidence concerns colorectal cancer. Dozens of large studies consistently show that high consumption of red meat raises the risk of colon and rectal cancer by roughly 10 to 22 percent compared with low consumption. Every additional 100 grams of unprocessed red meat per day is associated with 14 to 17 percent more risk. For processed meat the association is even more pronounced: just 50 grams more per day (a few slices of ham or one sausage) is associated with approximately 18 percent extra risk. This is the most solid finding in this field of research, supported by multiple independent analyses.
A clear association also exists for cardiovascular disease and type 2 diabetes. Across more than 4 million study participants, processed meat was associated with 26 percent greater odds of cardiovascular disease and 32 percent greater odds of diabetes per additional 50 grams per day. For unprocessed red meat those figures are lower. These findings are based on observational research, however: it cannot yet be stated with certainty that meat is the direct cause, because people who eat meat also tend to live differently on average.
Post-menopausal women who eat a lot of processed meat also have a somewhat higher risk of breast cancer according to multiple studies, roughly 6 to 9 percent. Elevated risks at high consumption of red meat have also been found for lung cancer, uterine cancer and liver cancer, but those findings rest on fewer studies. There are also indications that red and processed meat negatively affect the diversity of gut bacteria, although that evidence is even thinner than it is for cancer and cardiovascular disease.
What does this mean in practice? The elevated risks may sound alarming, but the absolute difference is more modest than the percentages suggest. If your baseline risk of colorectal cancer is relatively low, a 15 percent increase still amounts to a small absolute number. Nevertheless, the consistency of the findings across so many studies and cancer types is strong enough to take seriously. Limiting processed meat has the most solid evidential basis.
Based on multiple large meta-analyses and prospective cohort studies (up to dozens of prospective studies per analysis, more than 4 million participants for the cardiovascular disease analysis), as well as the official IARC classification of the WHO. The evidence is strongest and most consistent for colorectal cancer. For cardiovascular disease, diabetes and other cancer types the evidence is moderate to limited and largely observational.
Does red and processed meat really increase your risk of colorectal cancer?
Multiple large studies consistently show that high consumption of red meat, and especially processed meat, raises the risk of colorectal cancer. The evidence is strong enough to warrant consciously limiting your intake of processed meat (sausage, bacon, deli meats).
Does eating less red meat lower your risk of cancer?
Eating less red and processed meat probably lowers your risk of colorectal cancer, and possibly of several other cancer types as well. This concerns risk reduction, not complete protection.
Does eating processed meat such as sausage and ham give me colorectal cancer?
Eating a lot of processed meat measurably raises your risk of colorectal cancer by around 18-21%. Eating less sausage and ham, combined with more fibre, is the most evidence-backed step you can take yourself.
Does eating heavily heated or charred food increase your risk of cancer?
Heavily heated or charred meat likely increases the risk of certain types of cancer, although the associations in humans are associative. By not charring meat and varying cooking methods, you can substantially reduce your exposure to these substances.
Does being overweight increase my risk of cancer, and if so, which types?
Excess weight increases your risk of at least 13 types of cancer, including uterine, colorectal, breast and liver cancer. Losing weight reduces that risk, although it remains unclear whether all methods of weight loss are equally effective for immune defence against cancer.
Does eating a lot of sugar increase my risk of cancer?
Drinking large amounts of sugar-sweetened beverages is associated with a noticeably higher risk of certain cancers, particularly early-onset colorectal cancer and liver cancer. The association is observational, but consistent enough to make reducing soft drinks and fruit juice a concrete point of attention.