In response to the WHO announcement of the dangers of processed and red meat, as a vegetarian I could say "I told you so". But that wouldn't be the case – I'm not a vegetarian for health reasons.
But what I can do as a vegetarian is comment on the issue from a position of neutrality, or at least slightly more neutrality than someone who is having his favourite food labelled as cancerous.
There's been a few reactions from butchers who comment that we're evolved to be carnivores; wrong! We're evolved to be hunter-gatherers which makes us omnivores. Hunter-gatherers don't have meat every day, and even if they hit a particularly lucky streak it wouldn't be every meal. Essentually we're evolved to eat meat on an occasional basis – perhaps every other day.
And even if we're evolved for a hunter-gatherer diet, that doesn't mean to say that such a diet is the best possible diet for us. Although hunter-gatherers probably (if they avoided all the accident risks of such a life) lived longer than their agricultural cousins and descendents, that doesn't mean they lived long in comparison to modern expectations.
Processed Meats
Apparently the biggest risk is down to processed meats. But which ones?
Even I know that there are many different ways to process meat; or cure it. And if there are many different ways of curing meat, there are many different levels of risk. There are those who say that the risks associated with processed meats are to do with cheap processed meat, and proper bacon and sausages are fine. They could be right, or completely wrong. Who knows?
So it would be helpful to identify what level of risk is attached to each different processed meat. Or even more craftily perhaps someone can discover a new way of curing meat so we can have safe bacon and sausages (well, you anyway).
In the meantime, eat processed meat in moderation and to be safe seek advice on what "in moderation" means.
Red Meat
The risk of cancer associated with red meat is much lower than the risk associated with processed meat. Of course lower doesn't mean no risk, but just about anything has it's risks.
And the less red meat you eat, the lower the risk.
Cooking
This is a tiny bit speculative. There are a group of chemicals called nitrosamines which are nearly all cancer causing. They are formed in various different ways (particularly ways involving sodium nitrate which is added to cured meat to make it look red or pink), including two particularly interesting mentions: frying and the combustion of tobacco (i.e. smoking).
It is possible that exposing certain organic materials above a certain temperature forms nitrosamines; in other words cooking meat in ways that produces burning or charring could produce nitrosamines.
So you may be able to reduce the risk associated with that big lump of steak by eating it rare.
