I would like to see a study that controls for meat production methods, particularly prophylactic antibiotic and hormone treated CAFO raised beef and pork, vs. grass-fed / free range animals raised without antibiotics and hormones, under organic certification.

One set of studies specifically noted precursors of colon cancer conditions immediately following ingestion of red meat, with seems like a bad thing.

That said, I'm cautious but not convinced by these studies. I eat beef, though not daily.