From BBC News, reporting on article in the journal Circulation:

‘Sausage not steak’ increases heart disease risk

Eating processed meat such as sausages increases the likelihood of heart disease, while red meat does not seem to be as harmful, a study suggests.

A Harvard University team which looked at studies involving over one million people found just 50g of processed meat a day also raised the risk of diabetes.

But there was no such risk from eating even twice as much unprocessed meat, such as beef, lamb or pork.

This was despite the fact the two forms of meat have a similar fat content.  Researchers believe it may be the salt, not the fat, that’s the problem