In the latest science shocker, researchers discovered that a number of people around the world are eating foods such as cheese, butter and full-fat yogurt without doing deadly harm to their bodies. This was treated as health heresy, yet this study's findings weren't all that out of line with previous research on moderate consumption of so-called saturated fats, found primarily in animal products.
But people tend to greet any study with skepticism if it suggests a food that tastes good might not be killing us. There's something about deprivation we seem to associate with health and virtue.
It's hard to find commentary about nutrition that doesn't feature some version of the trope that we humans evolved in a state of semi-starvation, scrambling for whatever we could scrounge up. And now that food is abundant, the story goes, our innate wiring compels us to commit the deadly sins of gluttony by stuffing ourselves with globs of fat. It's like a version of the expulsion from Eden for the science literati. But it doesn't quite square with the data.
This recent fat-exonerating study, led by researchers from McMaster University in Canada, followed 135,000 people in 18 countries for around seven years. Its conclusion: Those who ate the most fat lived the longest. And it didn't seem to matter whether they ate saturated fat or the unsaturated kind, which is found in vegetable oils, fish and nuts.
Nutrition researcher Russell de Souza, who was involved in a previous analysis out of McMaster, said many doctors still believe in eliminating saturated fats because there have been several clinical trials on heart-disease patients comparing a standard diet to one in which saturated fats were replaced by vegetable oils -- so-called polyunsaturated fats. The people whose diets were changed did suffer fewer heart attacks than the control group.
These are controlled studies, which makes them very credible, he said. But their results don't back the conclusion that saturated fats are evil. In a subsequent study tracking 20,000 nurses, he said, some were asked to follow a normal diet of around 37 percent fat, and others were asked to cut that to 20 percent. What they found was that lowering fat didn't make the nurses healthier. Still, some noted that low-fat group only got down to 29 percent, leaving open the possibility that had they been more diligent about starving themselves of fat, they would have reaped great health benefits.
But such assumptions aren't particularly scientific. Alan Levinovitz, a professor of religion at James Madison University in Virginia, said that indeed, food gets tied up with people's suspicion of pleasure and desire. That's a central premise in his recent book, "The Gluten Lie and Other Myths about What You Eat." Food fads and fears, he said, can stem from the same human cravings that underlie religious beliefs -- myths, sin, ritual and the promise of salvation.
"Ultimately, people want to believe that our problem is our sinfulness and our sinfulness can be indexed to our choice of impure foods," he said. He sees a religious parallel in the culture surrounding the so-called paleo diet. Evolution stands in for God, he said, and the stone age for the Garden of Eden: "It was beautiful and everyone was happy and had rock-hard abs, and then we started eating the wrong foods and were kicked out of paradise."
To be fair to the paleo diet, there is growing evidence that certain modern inventions are harmful -- especially so-called trans fats, which are chemically altered to have a solid texture and were common in cheap baked goods and margarine. But one has to wonder why the medical community and government assumed that trans fats were healthy enough to launch on the public despite little initial data, and yet they are so reluctant -- even now, despite a growing body of evidence -- to say a little butter and cheese are okay. Could it have something to do with the fact that nobody really likes margarine?
It's not just fear but a mean-spiritedness that surrounds attitudes toward food and health, at least here in the United States. Popping up as the first comment on a recent New York Times story on fat and health was this sentiment: "How about [you] don't make a pig out of yourself every time you eat?"
But when it comes to fat, people aren't pigs. What's interesting about this newest study, said de Souza, is that it compared people with a wide range of eating habits from all over the world, and virtually no one among the thousands of thousands of participants ate more than 40 percent fat. Fat consumption tends to be self-limiting -- much more so than sugar. People don't routinely binge on sticks of butter, but they often consume massive amounts of sweet stuff in the form of big sodas. The sugar goes down easier, and it's cheap.
In the study, the people who had the shorter lifespans and higher disease rates were not the rich gluttons of the world who shirked the holy duty of personal responsibility. They were people from poorer countries who ate starchy diets -- most likely because that's what they could afford. It's nice imagine that a just God arranged things so that the starchy, cheap diets of the world's poorer people would endow them with health and longevity denied to all the rich gluttons dipping lobster in drawn butter. But if such salvation exists, there's no evidence it's happening in this life.
Flam is a Bloomberg View columnist. She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science, New Scientist and other publications. She has a degree in geophysics from the California Institute of Technology, and has been a Knight-Wallace fellow at the University of Michigan.