(Bloomberg Opinion) -- When the news broke last week that a new study has nutritionists again claiming eggs are unhealthy, I considered whether I needed to recant a 2016 column. There, I argued that declaring eggs and other real foods unhealthy back in the 1990s had driven people to make poorer food choices. Ditching eggs meant eating more cereal, muffins or oversized bagels with fake cream cheese.
But when I perused the results of the study, published in the Journal of the American Medical Association, I couldn’t see any evidence that eggs are worse than other things Americans tend to eat for breakfast.
The egg study wasn’t a controlled experiment but a so-called observational study, in which scientists pooled several studies on a total 30,000 Americans. At the outset, the subjects were polled about what they ate. Then researchers followed them for an average of 17 years to see who got heart disease, and who died. Those who reported at the outset that they ate more than one and a half eggs a day were 17 percent more likely suffer from heart disease than those who ate no eggs.
Knowing what this study reveals won’t change what happens when I’m on a road trip and end up in Dunkin Doughnuts, hungry. I’ll get one of the egg sandwiches, and I might still gently suggest to my travel companion that the egg sandwiches are the best options available, even as he insists that the coconut doughnuts must be healthy, because wasn’t there some study somewhere extolling the virtues of coconut?
It’s worth a close look to see what the egg study actually shows. Science writer Gary Taubes, who has spent years examining the flaws in nutrition science, lays out the problem with this type of study in this 2012 blog post. He focused on the health effects of meat, but the studies he criticizes were constructed much the same way as the new one re-examining eggs.
There are several reasons people who eat less meat would live longer, Taubes argued. One is that more affluent, health-conscious people are more likely to follow multiple health recommendations — including some that are misguided, but also some that work, such as not binge drinking or smoking.
That is, there could be nothing bad about meat and researchers might still get an association between eating lots of it and ending up unhealthy. And so it is with eggs, which were still widely considered unhealthy 17 years ago, when the study subjects were asked about their diets.
Even now, if I step into that other ubiquitous American breakfast stop — Starbucks — what I want is a breakfast burrito with vegetables. But you can’t get that. If you want the one with the spinach instead of some kind of processed meat, you can only get egg whites. So veggie lovers end up skipping the egg yolks, and we may be healthier because veggies are good, not because egg yolks are bad.
Despite my persistent skepticism over these egg scares, I myself would have to report that I eat at most three or four eggs a week — and not just because Starbucks refuses to serve real eggs and spinach in the same dish. It’s because I buy fast food meals only when I travel, and the rest of the time I think nothing of eating a tray of brown rice California rolls for breakfast, or leftover sesame-asparagus chicken, or chia seed pudding. If I live a long time, it might have nothing to do with eggs and much more to do with my eclectic taste and the fact that I can afford to eat sushi rolls for breakfast if I feel like it.
In the daily life of most Americans, the alternatives to eggs and bacon are probably cereal, pancakes with syrup, doughnuts, pastries or maybe oatmeal. What we really need is a study showing what the death rate is from eating, say, three or more doughnuts a week.
There was a study published just last month that lead to the claim that eating processed foods — including cereal — would kill you. This latter study was constructed in a similar way to the egg study, so it’s yet to be determined what’s causing the processed food-eaters to die earlier. But I consider it good reason to hesitate before switching from eggs to Frosted Flakes.
What is pretty well established is that when there was a public health campaign to curb smoking, it was followed by dramatic health improvements, and when health officials tried to do something similar with dietary fat and cholesterol, people got much fatter and diabetes rates soared. And so I still agree with Taubes that nutrition science flip flops not because there’s something wrong with the scientific method, but because nutrition isn’t using the method very effectively, and many studies aren’t constructed in a way that would help people make better choices.
Eventually, health recommendations should improve, but in the meantime, when I’m faced with a fast-food menu, I’ll still bet that the egg sandwich is healthier than the doughnut — even the one coated with toasted coconut.
Which is not to say that I declined to share my friend’s doughnut that day. Once in a while, such things can’t hurt.
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Faye Flam is a Bloomberg Opinion columnist. She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science and other publications. She has a degree in geophysics from the California Institute of Technology.
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