Emergent Fitness: People Just Won't Stop Picking on Saturated Fat!

That's what I call BREAKFAST!

As many of you may be aware, saturated fat has a rather infamous reputation. Ever since Ancel Keys published his study on the effect of high fat diets on heart disease risk decades ago, many have found cause to accuse dietary fat of doing the Devil's work. Of course, others are now calling dietary fat (particularly saturated, omega-3, and monounsaturated varieties) manna from heaven. What gives?!

While I have no intention of walking you through a step-wise history of how people have thought of dietary fat throughout the span of time, I do want to make one fact overbearingly and overwhelmingly clear: people can't agree about anything! (or at least that's how things appear at times) I can't stress enough the fact that the evidence for and against dietary fat (saturated fat included) is inconclusive at best. Some studies support its demonization, while other studies clothe it in garments of white; and both naysayers and yea-sayers alike will cherry-pick from both pools of studies to support their positions. I'll admit right now that even I'm biased (yes even me!). I fall into the "saturated fat is not evil" camp, so naturally, when I come across a study indicting saturated fat (or any fatty acid, save for vegetable oils, omega-6, and trans fat) I get wound up! I don't like hearing contradictory evidence, because I want and need certainty about my beliefs. But life, unfortunately, doesn't always treat me so graciously.

Bearing this whole mini-rant in mind, let's dive into a recently published study which, much to my chagrin, casts a shadow on my beloved saturated fat.

The Study

As Emily Coyle, writing for the Wall Street Cheat Sheet, reports:

"Researchers from the National Cancer Institute in Milan found that women who eat a diet high in saturated fat may be at an increased risk for several types of breast cancer." (1)

And, as Kathleen Doheny from WebMD also indicates regarding this same study:

"In a large European study evaluating more than 337,000 women in 10 countries over 11 years, researchers found that women who ate the most saturated fat were about 30 percent more likely to develop breast cancer than those who ate the least." (2)

So, according to this study, saturated fat is a boogeyman, at least as far as certain types of breast cancer are concerned. This hypothesis is a very narrow one; one that, according to Genevra Pittman, writing for Reuters, remains tenuous at best:

"Past studies have come to differing conclusions on a possible association between dietary fat and breast cancer. Whether the two are even linked at all remains controversial." (3)

Nevertheless, the study at hand suggests that there is a link between breast cancer and dietary fat. More specifically, the researchers believe that the link has to do with the effect of dietary fat on sex hormone production. As Pittman further writes:

"The researchers said it's possible dietary fat increases the level of sex hormones in the body. That could explain why high-fat diets are tied to a greater risk of tumors whose growth is related to estrogen and progesterone, known as hormone-receptor-positive cancers. Those cancers make up the majority of breast cancer diagnoses." (4)

Other research does seem to support this hypothesis, at least in regards to dietary fat's effect on sex hormone production in women (5). However, more research yet suggests that being overweight/obese may also link rather strongly with the production of sex hormones (6); thus leaving us to consider whether fat, in and of itself, is the true cause of "hormone-receptor-positive cancers," or if, rather, a diet high in calories may be to blame. Could it be the case that the women in this study who consumed more saturated fat were also consuming more calories? Moreover, might these women, therefore, have had a higher body mass index? I honestly don't know, but the question begs itself nevertheless.

In a previous post I wrote about a similar issue to the one here at hand, wherein I said the following regarding saturated fat:

"Little evidence exists to suggest that saturated fat is a boogeyman. As a matter of fact, there's very little evidence to indict or defend saturated fat...The only circumstance under which I would say you should cut back on your saturated fat consumption would be if you were consuming it to the detriment of essential fatty acids such as omega-3 and omega-6, and/or if you were consuming more calories than you ought to be eating, and this excess was coming from saturated fat." (7)

My 5 Cents

While this study does have an impressive sample size from which its authors draw their conclusions, I'm not convinced (I'm biased, remember!). In my opinion, losing excess weight and/or maintaining a healthy weight, regardless of the precise macro-nutrient breakdown of whatever diet you use to lose and/or maintain your weight, still remains the most important factor effecting disease risk. Hunger-gatherer groups, who represent some of the healthiest peoples in existence today, eat a wide variety of diets (in terms of both macro-nutrients, and food choices) all the while living lives free from most Western diseases of affluence (8). A healthy diet is not about what it boils down to, but what it amounts to*.