Dispelling nutrition myths, ranting, and occasionally, raving

Does fat cause breast cancer?



I don’t even have to read the study about high-fat diets causing breast cancer in teenage girls to say that it’s essentially meaningless. Just reading the news article pissed me off. Why? Because the headline reads: High Fat Diet Tied To Accelerated Breast Cancer Development In Teenage Girls. Oh no! Maybe we were wrong (again!) that fat isn’t the demon food we once believed it to be. Read a little further… “the researchers fed a group of female, pubertal mice a high fat diet”. Wait… So this study didn’t actually study human teenage girls? Well, how much fat is “high-fat”? And what type(s) of fats did these mice eat? Perhaps I do need to turn to the actual study after all.

Mice on the low-fat diet were given 10-12% of total calories from fat. Mice on the high-fat diet were given 60% of total calories from fat. The fat was from corn oil and lard. Mostly lard. Up to 54.5% of total calories came from lard. Can you imagine eating more than half of your calories in a day from lard? Presuming an average teenage girl needs 2, 000 calories a day (give or take a couple of hundred) that means that about 1, 080 calories come from lard! That’s more than 100 grams of lard. And that’s not even counting the calories from the corn oil!

The study found that the high-fat diet affected genes in the mice associated with breast cancer. Interestingly, the high-fat diet had no effect on weight (more evidence that calories do matter). Their conclusion was that a high-fat diet can increase the risk of breast cancer in girls, independent of weight status.

My conclusion: humans are not the same as mice. If you are a mouse eating obscene amounts of lard and corn oil on a daily basis you might have cause for concern. Even if you’re not a mouse, that’s too much lard.


Author: Diana

I'm a registered dietitian from Nova Scotia, living and working in Ontario, Canada. My goal is to help people see food and nutrition from a different perspective and understand that nutrition and health are not necessarily a result of personal choice.

3 thoughts on “Does fat cause breast cancer?

  1. Good post. In the age of quick and flashy news, does anybody really take the time to have a look at the methods in these broad sweeping medical studies?


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