You already know to go easy on the red meat, since diets heavy in hamburgers, prime rib, and other high-calorie animal proteins have been linked to greater risk of heart disease, cancer, and shorter lifespans. Occasionally you might splurge on a choice New York strip or juicy bacon cheeseburger, and that's totally okay – but the way you or the restaurant chef cook it may not be. A recent study shows that eating red meat that's been pan-fried can raise your risk of prostate cancer by 40 percent. The cause? Chemical carcinogens that get churned up within the meat when it's cooked at scorching temps.

"Pan-frying allows meats to reach very high temperatures, likely higher than through other methods," says Mariana Stern, lead researcher and a professor of preventive medicine at the University of Southern California's Keck School of Medicine, where the study took place. "It requires using fats or oils that act as an efficient heat-transfer medium between a very hot pan and the surface of the meat." But then it's the high internal temp the meat reaches that becomes the real problem, Stern says. "The higher the temperature and longer the cook time, the more carcinogens accumulate," she explains.

Stern's team discovered that pan-fried hamburger was more of a carcinogen bomb than steak cooked in the same fashion. "We speculate this is because hamburgers, due to their composition and texture, can attain high external and internal temperatures faster than steak," Stern says.

You may have heard that barbecuing or grilling over open flames also can cause carcinogens to form. That's true, but Stern says these are mostly polycyclic aromatic hydrocarbons, which aren't as harmful for the prostate as the heterocyclic amines that accumulate internally when meat is pan-fried.

To minimize your carcinogen exposure, Stern says to use lower-temperature cooking methods such as baking whenever possible and to limit intake of pan-fried red meat, in particular hamburger, to less than once a week. And when you do pan-fry it, turn down the stove. "Meat has to be cooked to an internal temperature of 158 Fahrenheit in order to prevent growth of harmful bacteria, but if you heat the pan to 160 F instead of a much hotter 250 F, it extends cooking time by only two minutes and can dramatically reduce the amount of carcinogens that form," she says.

Stern adds that marinating meat in soy-based Asian-style sauces and microwaving it before cooking can also curb carcinogen formation.