Sweet And Sour: The Media Decided Fructose Was Bad For America; But Science Had Second Thoughts
This article by Trevor Butterworth originally appeared on Forbes.
For the past decade, a specter has haunted the food chain—the specter of high fructose corn syrup (HFCS). HFCS began life as a technological response to a market problem—volatile prices for sugar in the 1970s and early 1980s driven by protectionism and dumping, along with high production costs and all the challenge of matching a multi-year crop to shifting demand. HFCS aimed to stabilize the cost of sweetness. It did; and in doing so, it conquered the US market.
But HFCS had, like Achilles, a weakness—actually, two. First, as many scientists have noted, high fructose corn syrup wasn’t really high in fructose—and its other primary component was glucose. The sweet spot in balancing fructose with glucose was roughly a ratio of 55 percent to 45 percent—the same as honey—and not dissimilar to ordinary table sugar, which has a ratio of 50:50.
The second weakness was timing. The spread of HFCS coincided with the beginnings of the obesity crisis—or more specifically a point where people were beginning to tip over the BMI boundary lines from normal to overweight and overweight to obese. This, as we now know from the work of John Komlos, was a long time in the making: BMI values began to rise—and rise dramatically—in the 1950s, but the sudden appearance of massive weight gain in the population led some scientists to wonder whether it might be connected with this new fangled ingredient.
The result was a study in the American Journal of Clinical Nutrition (AJCN) 2004— “Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity”—which noted that “The increase in consumption of HFCS has a temporal relation to the epidemic of obesity, and the overconsumption of HFCS in calorically sweetened beverages may play a role in the epidemic of obesity.”
Just as people glom onto miracle diets and miracle foods, they also look for the Darth Vader ingredients—those which use the force of taste to take over our bodies. HFCS was new, it was from corn, it was high in fructose. And it provided a simple solution to a hugely complex problem of why America was suddenly in the grip of obesity.
But was this, “important potential hypothesis,” for the obesity epidemic (as the authors of the study wrote) true? The point of science is to advance hypotheses, test them, and arrive at some level of causal validity. Were obesity and metabolic syndrome a result of Americans generally eating too much food and being inactive, or was there something to fructose that was distinctly bad—and hence a major cause of weight gain—as opposed to it being one factor among many? So began one of the major controversies of the obesity crisis.
In 2008, the American Medical Association passed a resolution at its annual conference saying that there was insufficient scientific evidence to indict HFCS as a unique contributor to obesity. At the same time, it also said that the scientific literature on the issue was very limited. In 2012, the Academy of Nutrition and Dietetics (formerly the American Dietetic Association) concluded that the research—now more expansive— provided “little evidence that HFCS differs uniquely from sucrose and other nutritive sweeteners in metabolic effects.”
The authors of the original AJCN study continued to maintain that fructose might be more of a problem than sugar because of the ongoing research on metabolic differences between the two. And they were joined by pediatric endocrinologist Robert Lustig, who took fears about the effects of fructose and sugar on the population to a whole new level. Fructose, he contended in a much-watched YouTube lecture, and later a book, is poisonous—the toxic part of sugar.
It’s not unfair to say that this was a position that won Lustig many critics and very few converts among scientists. As Scientific American pointed out, one key problem with Lustig’s argument is that “concern about fructose is based primarily on studies in which rodents and people consumed huge amounts of the molecule—up to 300 grams of fructose each day, which is nearly equivalent to the total sugar in eight cans of Coke—or a diet in which the vast majority of sugars were pure fructose.”
Mike Gibney, Director of University College Dublin’s Institute of Food and Health, concurred, “The majority of animal studies used as much as 55% of calories from fructose, a situation, which is impossible to envisage in the human diet except maybe in the make-believe land of milk and honey.”
Lustig also ignored the double whammy of increases in consumption of other foods besides sugar and a decrease in physical activity over the past 40 years, wrote fitness and nutrition expert Alan Aragon.
In a report on the controversy over Lustig and fructose, David Klerfeld, a national program leader in Human Nutrition for the USDA, told ABC News, “So many things have happened in our environment in the past fifty years, from a total increase in calories to a decrease in activity—it’s absurd to pin the entire obesity problem on a single food such as fructose or even sugar consumption as a whole. Why aren’t we focusing on ginormous portions rather than wasting time looking at single ingredients?”
And Walter Willett, chair of the nutrition department at the Harvard School of Public Health (and no fan of soda or the food industry) told The Washington Post, “Telling people the problem is all fructose is completely wrong.”
But who exactly was telling people this? Why are we wasting time looking at single ingredients instead of overall diet and activity? The direction of the research, the consensus statements by professional associations, the comments by frustrated nutritionists—all converged on a simple message. Why did that message seem to be muffled, unheard, untaken?
According to a new study, blame the news media.
Now, obviously not every news story, for the ones cited in this article from ABC News, The Washington Post and Scientific American are all highly informative, and ascend (in my view) in orders of excellence. But when you look at the news media coverage ecologically, do these kinds of stories drive both journalistic and public understanding over time?
The study, by colleagues at the Center for Media and Public Affairs at George Mason University, attempted to answer this question by looking at media coverage of HFCS and fructose over the past ten years beginning with the 2004 AJCN paper.
They focused on ten additional significant “research events,” mostly the release of new studies but also an interview or editorial or conference presentation, which marked the evolution of the scientific debate in the succeeding years within the scientific community. The ten events were divided equally between both sides of the fructose debate. A month’s worth of media coverage around each event provided a sample of 567 news stories in 120 news outlets.
The results are overwhelming: 90 percent of the coverage went to the reports critical of HFCS. Reporters and sources spoke of HFCS as either a proven cause of obesity and other adverse health effects (37 percent) or a suspected cause (46 percent). Most stories failed to provide any scientific details about how the experiments were done or how they fit in with previous experiments.
And in one of the oddest findings, as the field of nutrition and public health became more convinced that fructose was effectively no different than sugar, the media coverage became more certain that it was. Before the 2012 statement by the Academy of Nutrition and Dietetics, 63 percent of media sources affirmed an equivalence between fructose and sugar, but afterwards this shifted to 71 percent of sources denying such an equivalence.
Is this a result of the “Lustig effect”—when you have an expert source entering a discussion with rhetoric so loud and extreme it drowns out any other perspective? Could be: it turns out that Lustig was the most frequently cited expert source in the media coverage (21 quotes)—followed by Barry Popkin (20), one of the co-authors of the original AJCN paper.
The bigger problem with the overall media coverage is not just that it valorizes those who shout fire in a crowded theater or advance an “important potential hypothesis” while ignoring those who say, “we don’t see a fire; we can’t validate your hypothesis,” it’s that science has been replaced by opinion. Sure, journalists were willing to let Lustig play them like an musical—Oh Fructose! —but when all the assertions about sweeteners were added up (1,512), the study found that only 16 percent were backed up by referring to any scientific evidence.
That’s a whole lot of assertion.
Now, some will instantly dismiss these findings because the study was supported by a grant from the Corn Refiners Association, but content analysis is basically counting—a very exacting and tedious way of counting but still… counting. If you think the results are skewed, you can do your own study of the media coverage, challenge the conclusions, and glory in participating in the scientific method.
But there are some quite robust facts: Nine years after the fructose hypothesis was advanced, there is a paucity of evidence to show that it has played a special role in causing obesity over any other caloric sweetener; there is little evidence that moderate consumption of HFCS has a different impact on the body to moderate consumption of regular sugar, when all dietary calories are equal. There is a lot of evidence that many scientists in the nutrition and public health fields are weary of the focus on fructose; and there is now, with this study, evidence that all this has been and is being largely ignored in the news media.
One thing is guaranteed. The more science we do the more surprising results we are likely to find. Perhaps a study will come along and conclusively prove that fructose is different from all the other sugars, and HFCS is Darth Vader. Until then, one notes, ironically, that the most recently published research on fructose, a pooled analysis of 20 controlled feeding trials found that it had some metabolic effects different to glucose but that it could “also have important advantages over glucose for body weight, glycemic control, and blood pressure.” There was no net benefit, the authors concluded, from switching from one to the other as opposed to reducing the consumption of each. One might say, “read all about it,” but…
Trevor Butterworth is editor-at-large for STATS.org