[dspillett]

My first thought was that the report is only talking about rectal and colon cancers, so yes diet might affect them as much as (or even more than) smoking.

But that really isn't even close to to being a good comparison when discussing overall effect of risk factors: talking about the effect of smoking while only counting damage to the bottom end of the digestive system is like talking about the effect of drink driving while only counting uni-cyclists.

So the reporting is massively misleading, the inference that the risks caused by smoking and those caused by eating processed meats are even of the same order of magnitude is simply wrong. I shall have to read the actual report to get any real meaning from it.

[debacle]

From what I've read on /r/science eating 100g of the specified meats daily increases your risk of certain cancers by ~20%.

Compare with smoking, which increases the risk of lung cancer by 1,000-1,500%

[tkyjonathan]

Here are some actual studies (impact factor between 7.5 to 17) showing the connection between meat and cancer. This was probably part of the 800 studies that the WHO used to make its decision.

http://www.ncbi.nlm.nih.gov/pubmed/24606898

http://www.ncbi.nlm.nih.gov/pubmed/21422422

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2121650/

http://www.ncbi.nlm.nih.gov/pubmed/23169929

http://share.kaiserpermanente.org/article/high-fat-dairy-pro...

http://www.ncbi.nlm.nih.gov/pubmed/22342103

http://www.ncbi.nlm.nih.gov/pubmed/14585259

http://www.ncbi.nlm.nih.gov/pubmed/19279082

[URSpider94]

No, the article draws an analogy between the impact of meats on colon cancer and the impacts of cigarettes on lung cancer. They are not talking about the impact of smoking on colon cancer.

[zsupalla]

Exactly! I'm always disappointed by reporting on scientific research; reading the research helps, but how many people are going to do that? A lot of people will probably change their diets based on this research, assuming that eating meat is as bad as smoking.

[tkyjonathan]

Sorry, guys, but you are all wrong. WHO is a huge and difficult body to get agreements from. After years and 800 studies, they decided today to label processed meats as carcinogens.

Btw, 15% of lifelong smokers get lung cancer whereas 15-19% of meat-eaters get some sort of cancer (mainly, colorectal, prostate and breast).

I can appreciate that this is a surprise, but the data has been there for more than a decade.

[AlisdairO]

You haven't established that cancer in meat eaters is largely caused by eating meat, whereas it is quite clear that overall cancer rate drastically increases in smokers.

In fact, while vegetarian diets do reduce the risk of cancer, the difference is by comparison modest - the overall risk of cancer in vegetarians is ~10% lower.

[tkyjonathan]

That isn't true. There are causal links between meat and cancer. You have: IGF1, saturated fat, sulphar-based animo acids like methionine, mycobacterial load, oxidative stress, purification in the intestine and more recently, that nuXX sugar found in protein.

[AlisdairO]

Did you read my comment?

I didn't deny causal links between meat and cancer. I denied that the causal links between meat and cancer caused anything close to as much additional total cancer risk as smoking does. That's a viewpoint that is supported by any credible source you care to name.

[tkyjonathan]

Vegetarians still consume proteins from animals like casein and cholesterol from eggs. There have been a lot of studies connecting casein to cancer as well (when protein intake is over 7% from calories).

[zsupalla]

This is a perfect example of confusing correlation with causation.

[DanBC]

The WHO report is very clear: red meat and processed meat cause an increase in risk of some cancer. And they're very clear that it's causal, not just correlation. And they're clear that the risk is increased by 15-20%. But that increase is on a very low risk.

[tkyjonathan]

"This is a perfect example of confusing correlation with causation." You are confusing two different fields of science. This isn't physics where an action causes a reaction. This is biology and the human body is a massive ecosystem. The 800 studies that "eventually" reached the WHO is the best way to determine a connection between two things. This is decades of research and maybe around 1million human subjects that were studied in total.