Patients often come see me because they are confused about all of the conflicting information they are getting about nutrition. Last week, tomatoes were good. This week, they will make your pancreas explode. Last week, fish were full of mercury and should be eaten only every third Sunday in months with the letter "t" in them. This week, damn the mercury, get those omega 3 fatty acids! It seems that every day there is a new study coming out that conflicts with last week's study.
There are two sources of this confusion. The first is the demands of mainstream news processing and distribution. By the time the media is finished with a useful news item, it has usually been stripped of any valuable content, much like what happens to an ear of corn on its way to becoming a Doritos chip. It is then unsurprising that conflicting information should appear, sometimes stemming from the same study.
The second source of confusion is the frequent poor quality of the research itself. If you have a background in the sciences, and you actually read the articles themselves, rather than the abstract, you often begin to wonder how on earth the authors reached the conclusions that they did.
It is a little bit like looking at a painting and thinking to yourself, "what a beautiful study in yellow I see here," then having the artist walk up and tell you how red the whole thing is. You just have to shake your head and wonder.
Which is exactly what I did when I came across this little gem of an article, "A High-Fat Meal Increases Cardiovascular Reactivity to Psychological Stress in Healthy Young Adults." (Article here.)
At first blush, this is right up my alley. Nutrition, mind/body interaction, cardiovascular disease, gee, I couldn't ask for more out of a journal. And the conclusion was very interesting. "The consumption of high levels of saturated fat over the course of several weeks may lead to exaggerated cardiovascular reactivity," the authors wrote. In fact, "the consumption of a single high-fat meal has been associated with a transient impairment of vascular function."
Translation: A high-fat meal is bad for your heart and arteries.
It would seem to be common wisdom, after all, that's the party line that has been thrown at the public over the past 20 years. But the party line, as we know all too well, is rarely the whole truth.
Comparing junk to junk
Which it turns out, is the case here. The high fat meal consisted of 2 McDonald's hash brown patties, a Sausage McMuffin and an Egg McMuffin. Holy Toledo! But wait -- the "healthy" meal included Kellog's Frosted Flakes, skim milk, Source fat-free yogurt, a Kellogs Fruit Loops Fruit Bar and Sunny Delight orange juice.
In short, both meals were nutritionally unsound. The low-fat meal turns out to be a high-sugar meal, also accompanied by hormones, antibiotics and a cornucopia of chemical additives, most of which have unknown effects on physiology.
Perhaps that did not matter to these investigators. However, were I conducting nutritional research, I would choose a nutritionally balanced and healthy meal as my baseline. All we are doing here is comparing junk to junk.
"All well and good," some might say, "but it still tells us about the effects of fat on the heart."
It actually tells us nothing of the kind. There were no controls in place for any of the following:
1. Hormones, which are known to exist in physiologically effective concentrations in the meat sources used by McDonald's and other fast-food chains;
2. Antibiotics, also present in physiologically effective concentrations;
3. Trans fats and unsaturated fats, which have significantly different cardiovascular effects;
4. Sugar. Although the long-term ingestion of high amounts of sugar eventually lead to ongoing high blood pressure, the immediate effect of eating sugar is to temporarily lower blood pressure.
So not only were the researchers comparing junk to junk, they also failed to control for significantly important nutrients which could influence the outcome, and in particular, chose a baseline meal that would have the effects of exaggerating the outcome of the experiment.
In short, in addition to using junk nutrition, these researchers produced junk science.
Nonetheless, it will be cited in yet other journal articles as yet more proof that high-fat diets are bad for your health.
When, actually, this research said much and proved nothing.