A Mediterranean style diet is an ideal diet to reduce the risk of breast cancer. Specifically, it is low in saturated fat and red meat, and high in fiber.

Fats

The type of fat a woman eats is important. A meta-analysis showed that death from breast cancer was higher in the women eating more saturated fat compared to the women eating the lowest amounts of saturated fat. The Mediterranean Diet is low in saturated fat.

Red Meat

The big picture data about red meat and breast cancer so far is inconclusive, some studies show increased risk and some show no association with breast cancer. That being said, multiple studies on the risk side show >5 servings of red meat per week will increase a woman’s risk of breast cancer. In my opinion, it is cautious to limit, but not strictly avoid red meat. This is also important because red meat has stronger data to support it causing other types of cancers. The Mediterranean Diet has limited red meat intake, it is a plant-based diet.

Fiber

Fiber is a protective factor, with 12% less relative risk of breast cancer for women with high fiber diets, shown in a meta-analysis of 24 studies. The Mediterranean Diet is high fiber.

Here is a table of a typical Mediterranean Diet. I have tweaked the recommendations to make them more specific for breast cancer and given my rationale.

Food	Recommended Intake	Serving Size	My Recommendations
Vegetables	3+ servings per day	½ cup	5 servings a day; fiber.
Fruit	3 servings a day	Tennis ball size portion
Nuts	3 or more servings a week	¼ cup	1 serving a day to ensure adequate protein on a plant-based diet.
Beans/soy	3 or more servings a week	½ cup	1 serving a day to ensure adequate protein on a plant-based diet.
Whole grains – healthy whole grains include brown rice, oats, corn, quinoa, barley, 100% whole wheat bread and whole wheat pasta.	4 or more servings a day	½ cup or 1 slice of bread	If you went up on beans and nuts for protein, limit whole grains to 3 servings a day (1.5 cups) and only one serving of bread. Some women will gain weight if eating more than 1.5 cups of grains per day.
Fish	1-3 servings per week	4 ounces	Prefer wild salmon, sardines, herring for omega-3 fats.
Fats – high quality extra virgin olive oil (EVOO)	1-4 TBSP per day		I heard an Italian Naturopath at a cancer conference say she tells all of her patients 4 TBSP EVOO a day!
Poultry, eggs	Daily to weekly	3 ounces	Up to 3 times a week, these are sources of saturated fat. Prefer organic poultry; U.S. chicken is high in estrogen.
Dairy products – yogurt, cheese	Daily to weekly	Varies	Unsweetened yogurt up to daily, cheese used sparingly.
Red Meat	0-1 serving a week	3 ounces	Red meat is high in saturated fat.
Wine	1 serving a day	5 ounces	With cancer in mind, I would limit this to 1 serving 3 times a week and if you are a breast cancer survivor consider avoiding altogether.
Refined flour – white bread, white pasta	Avoid		Avoid.
Sweets	Avoid		Use fruit as a dessert.

References

1. Alexander DD, Morimoto LM, Mink PJ, Lowe KA. Summary and meta-analysis of prospective studies of animal fat intake and breast cancer. Nutr Res Rev. 2010 Jun;23(1):169-79. doi: 10.1017/S095442241000003X. Epub 2010 Feb 25. PMID: 20181297.
2. Farvid MS, Stern MC, Norat T, Sasazuki S, Vineis P, Weijenberg MP, Wolk A, Wu K, Stewart BW, Cho E. Consumption of red and processed meat and breast cancer incidence: A systematic review and meta-analysis of prospective studies. Int J Cancer. 2018 Dec 1;143(11):2787-2799. doi: 10.1002/ijc.31848. Epub 2018 Oct 3. PMID: 30183083.
3. Chen S, Chen Y, Ma S, Zheng R, Zhao P, Zhang L, Liu Y, Yu Q, Deng Q, Zhang K. Dietary fibre intake and risk of breast cancer: A systematic review and meta-analysis of epidemiological studies. Oncotarget. 2016 Dec 6;7(49):80980-80989. doi: 10.18632/oncotarget.13140. PMID: 27829237; PMCID: PMC5348370.