This published today pointed me in the direction of the study which needs full access to view. Basically, eating red meat will increase the risk of pancreatic cancer in men; processed meat will do the same in both. This led me to remember the link between Multiple Sclerosis and red meat, information on which I found here. There is also an association between arthritis and red meat, the article for which is on the BBC news page, but there's no link to the original source.
The idea of this all is that red meat mimics certain proteins in our immune system, and the body goes into overdrive trying to remove those foreign bodies. Too much red meat means too many of these proteins, and your body will literally start attacking itself. Not to wax lyrical, but meat isn't the healthiest thing to eat. Then again, neither is not exercising healthy; or over-consuming alcohol; or smoking; or living in a city etc. In the case of red meat with MS, moderation is actually not the best policy - abstinence is.