The International Agency for Research on Cancer (IACR)’s announcement that processed meat is a cause of cancer, and that red meat is a probable cause of cancer, needs to be taken in the context of what these classifications mean.
Crucially, these classifications don’t indicate the size of the risk, how many cases of cancer they cause, or what sort of dose is needed. Group 1, into which processed meat, includes tobacco smoking, alcoholic drinks, air pollution and sunlight. Group 2A includes things which IARC believe are probably carcinogenic, but for which there is insufficient evidence to be more definitive. DDT is an example of a group 2 “probable carcinogen”, but so are burning wood for fuel, high temperature frying, or working as a hairdresser. Again, the classification only relates to the quality of the available evidence, not the magnitude of the risk. The cancer risk from tobacco is much, much higher than the risk from eating processed meat, despite reports in some of the media covering this. Unless you are eating very large amounts on a regular basis, the increase in cancer risk is relatively very small.