We hear a lot in the news about the health risks of red meat. But it seems that processed meats, such as bacon and cold cuts, may pose an even greater risk of heart disease or diabetes, according to a Harvard School of Public Health study published on the website of the journal Circulation.

For the study, researchers analyzed almost 1,600 other studies. These studies evaluated more than a million people from 10 countries on four continents: North America, Europe, Australia and Asia.

The people who ate processed meats—those described as preserved by smoking, salting or curing (for example, bacon, sausage, salami, hot dogs or cold cuts)—had a 42 percent higher risk of heart disease and a 19 percent higher risk of type 2 diabetes, researchers said.

Meanwhile, people who ate unprocessed red meat (beef, lamb or pork) didn’t show any increased risk of heart disease or diabetes.

Researchers noted both processed and unprocessed meats eaten in the United States had similar quantities of saturated fat and cholesterol, but the processed meats had 50 percent more nitrite preservatives and four times more sodium. (Salt is known to increase blood pressure, while nitrites simultaneously harden the arteries and increase glucose tolerance—a risk factor for diabetes.)

In other words: It’s a good idea to cut back on processed meats. But you don’t have to cut them out of your diet completely, said Renata Micha, a research fellow at the Harvard School of Public Health in Boston, and one of the study’s coauthors.

“Based on our findings, eating one serving [of processed meats] per week or less would be associated with relatively small risk,” Micha advised.

For more about the health effects of red meat, click here.