So how much is OK to eat? The World Cancer Research Fund recommends that you eat no more than 500 grams (that’s 18 ounces) of red meat a week; that’s about three regular-sized burgers. Harvard Health, a blog published by the Harvard Medical School, recommends that red meat should only make an appearance in your diet only every “now and then,” and that instead, you should eat fruits, veggies, whole grains, beans nuts and seeds each day, along with small portions of cheese, yogurt, fish poultry or eggs each day.
The type of meat matters as well. The WCRF advises that “very little if any” of the red meat you eat should be processed, and the WHO report classifies the processed meats as more dangerous than fresh red meat.
Consumers should also avoid searing their meat at high temperatures, says Jayson Calton, who holds a PhD in human nutrition and co-authored the book “The Micronutrient Miracle: The 28-Day Plan to Lose Weight, Increase Your Energy and Reduce Disease”. This searing, he says, has been shown to cause cancer — a finding that research backs up. (The reason: Two chemicals, heterocyclic amines and polycyclic aromatic hydrocarbons, form on meat cooked at high temperatures, such as when you pan fry or grill directly over an open flame; both have been shown to cause changes in DNA that may increase the risk of cancer.) To avoid this, Calton recommends that you turn down the heat to less than 300 degrees Fahrenheit, turn meat with tongs (since forks can puncture the meat, which causes the flame to flare up), flip meat frequently and avoid overcooking.
There is also some evidence that grass-fed beef has cancer-fighting properties. A study published in the Nutrition Journal, which examined three decades of research on grass-fed versus grain-fed beef, found that grass-fed beef has twice the level of conjugated linoleic acids (which may have cancer-fighting abilities) than does grain-fed beef (as well as a host of other perks like lower levels of unhealthy fats and higher levels of omega-3 fatty acids, vitamins A and E, antioxidants). But despite that, it’s not clear that those perks have much impact on human health.