Doctors have known for millennia that there's a relationship between diet and health - some things you eat make you sick, and others help you stay healthy. Now researchers are exploring the relationship between eating meat and health, and they're finding that eating some kinds of meat can actually shorten your life.

Previous studies found that people who eat large amounts of red meat are more likely to develop colon cancer and cardiovascular disease. Researcher Rashmi Sinha from the U.S. National Cancer Institute studies meat and wanted to know more about its relationship to premature death.

"Meat is a very important part of our diets," she says. "People have been interested in the relationship of different types of diets, of different components of the diet and disease."

Sinha looked at data from a very large decade-long study of older adults.  To do the study, researchers asked more than half a million adults in their 50s and 60s about their habits and lifestyle. They collected information on things such as height, weight and family history of disease. Subjects also answered detailed questionnaires about their diet.

"We looked at red meat, which included beef and pork; white meat, which is poultry and fish; and processed meat, which included cold cuts and luncheon meats, hot dogs, bacon, sausage... basically processed meat, both white and red meat," Sinha says.

After analyzing at 10 years of data, Sinha found people who ate the most processed and red meats - about 100 grams a day - had a higher likelihood of dying, compared to those who ate the average amount of these products. 

Sinha says she looked primarily at deaths from heart disease and cancer. 

"For red meat, there was an increased risk of around 31 percent of total mortality in men and 36 percent in women," she says.

And Sinha found that people who ate more white meats actually had a decreased risk of death. She says she's not sure what it is about processed and red meats that might make them contribute to premature death. She says it would probably be better to eat less of them. However, Sinha also noted that the negative effect of meat was small in comparison to some other factors, such as cigarette smoking.

Sinha's research is published in the Archives of Internal Medicine.