b4d1ced9_sity_of_Michigan_Health_System__Why
[Recommendation] Choose your fat wisely [Why] 
Women in countries that eat high amounts of meat and dairy fat have a high breast cancer risk, while women in countries that mostly eat rice, soy, vegetables, and fish have a low risk. High-fat diets increase the risk of mammary cancer in animals.36 From country to country, breast cancer risk in women is proportionate to the level of total fat consumed in the diet.37 Estrogen levels, body weight, and breast density have all been reported to decrease when women are put on low-fat diets—all changes that are thought to reduce the risk of breast cancer.38 , 39 , 40 , 41 Moreover, breast cancer patients have been reported to reduce their chances of survival by eating a diet high in saturated fat.42 (Saturated fat is found mostly in meat and dairy fat.) Similarly, breast cancer patients have been reported to be at increased risk of suffering a recurrence if they eat higher levels of fatty foods, such as butter, margarine, red meat, and bacon.43 Analysis of human trials, using a research design dependent on the memories of subjects, also has shown women consuming high-fat diets to be at high risk of breast cancer.44 In some cases, the correlation has been quite strong.45 However, most,46 , 47 , 48 but not all,49“prospective” studies—which avoid problems caused by faulty memories—have not found any association between fat intake and the risk of breast cancer. Why do some research findings suggest that fat increases the risk of cancer and other studies find no association? Some studies finding dietary fat unrelated to cancer risks have not factored out the effects of olive oil or fish fat; both may protect against cancer.50 , 51 , 52 , 53 Adding them to the total dietary fat intake and then studying whether “more fat causes more cancer” is therefore misleading. Some studies finding no association between fat intake and breast cancer have made one or both of these errors.54 , 55 Scientists know cancers caused by diet most likely occur many years after the causative foods are regularly consumed. When one group of researchers compared dietary intakes to cancer rates occurring ten years after the consumption of food, and also eliminated from consideration the effect of fat from fish consumption, they found a high degree of correlation between consumption of animal fat (other than from fish) and the risk of breast cancer death rates for women at least 50 years of age.56 In the debate over whether dietary fat increases breast cancer risks, only one fact is indisputable: women in countries that consume high amounts of meat and dairy fat have a high risk of breast cancer, while women in countries that mostly consume rice, soy, vegetables, and fish (instead of dairy fat and meat) have a low risk of breast cancer.57
Breast Cancer Prevention (Holistic) | University of Michigan Health System