The research: For 20 years, the study team tracked the diet habits and breast cancer rates of more than 88,000 women between the ages of 26 and 45. The more red meat a woman ate, the more likely she was to develop breast cancer during the study period. Specifically, every daily serving of cow meat increased a woman’s risk for breast cancer by 13%, according to the study data. But swapping out servings of red meat for poultry, legumes (like beans and lentils), nuts, and fish lowered a woman’s breast cancer risk by 14% to 17%, the study shows. What it means: Cancer-causing byproducts are released when red meat is cooked at the high temperatures associated with grilling and broiling—one possible explanation for the cancer-cow link, explains study co-author Maryam Farvid, PhD, of the Harvard School of Public Health. The hormones, animal fat, and preservatives found in red meat could also explain the spike in breast cancer rates among the most enthusiastic cow eaters, Farvid adds. Why is red meat so risky in young adulthood? While Farvid couldn’t say for certain, her research suggests cutting back on red meat earlier in life may spare your body from years of heavy exposure to all of those potential cancer-causers.  The bottom-line: Farvid says swapping out red meat for the foods listed above appears to be a beneficial way for women—especially younger women—to ward off breast cancer. (Not sure you can give up red meat altogether? Here’s the case for doing it part-time.)