Let me be straight. I don’t believe in conspiracy theories.* There’s no Bacon-gate. No Cowspiracy. No Salami-mafia out to suppress sandwich meat. But, as the students in my Introduction to Science, Technology, and Society course will tell you, there are professional interests (only one of which is funding) and careerism. There is also the human desire to simply not be wrong. In nutrition, this desire is personal.
(If I were queen of the world, every research article published about nutrition and chronic disease would list, in addition to “author affiliations” and “conflicts of interest,” what each researcher typically eats for breakfast every day. You’d find out a lot more about “affiliations” and “interests” from that information than from anything else.)
And so there is this: Meat and fat intake and colorectal cancer risk: A pooled analysis of 14 prospective studies. It’s an abstract from the Proceedings of the American Association of Cancer Research, from back in 2004. It found:
Greater intake of either red meat (excluding processed meat) or processed meat was not related to colorectal cancer risk.
Typically, such abstracts are presented at a conference, then later published. This one never made it publication. We don’t know why.
Trevor Butterworth does some speculating about the “whys” here:
When contacted by STATS.org, Smith-Warner said they wanted to add a few more studies before publishing their results next year. But the fact is that their colorectal cancer study had more subjects than many of the other studies published by the Pooling Project – and the four-year delay in publication cannot but raise the question of whether their results just didn’t fit in with the nutritional beliefs of Harvard’s School of Public Health, one of whose senior figures – Dr. Walter Willett – has long recommended limiting red meat and who, coincidentally, is a board member of the World Cancer Research Fund.
It’s not the first time studies that contradict the status quo in nutrition never made it publication. This study also never got past conference proceedings, though there was an article about it in the Harvard Gazette and Walter Willett (who certainly seems to practice what he preaches) has his name on the abstract:
Greene, P., Willett, W., Devecis, J., and Skaf, A. (2003). Pilot 12-Week Feeding Weight-Loss Comparison: Low-Fat vs Low-Carbohydrate (Ketogenic) Diets (abstract presented at The North American Association for the Study of Obesity Annual Meeting 2003), Obesity Research, 11S, 95-OR.
Greene’s study found that a higher calorie low-carb diet resulted in more weight loss than a lower-calorie low-fat diet. I’m not arguing about what this study might prove about diets in general, so back off, all you folks out there foaming at the mouth to pick it apart. Truth is, you can’t really critique it, because it never got published.
Another study that almost didn’t make it out of the gate concluded that:
Our findings do not support the hypothesis that a diet consistent with the 2005 DGA benefits long-term weight maintenance in American young adults.
In a nutshell, Daisy Zamora found that black participants with a higher Diet Quality Index (according to the Dietary Guidelines for Americans) gained more weight over time than whites (with either a higher or lower Diet Quality Index). More surprisingly, these black participants also gained more weight over time than blacks with a lower Diet Quality Index.
Again, I’m not arguing the strengths or shortcomings of this research. The part of the story that matters here is that Zamora worked on this study as part of her PhD research at UNC-Chapel Hill. She found a tremendous amount of resistance to her findings, to the extent that she was counseled to “redo” her work without examining racial differences.
I’ve been hip-checked into the rails by the politics of nutrition science myself.
I guess that’s why, to some extent, I feel that all of the talk about “good” science vs. “bad” science in nutrition is misplaced. How do we even know that the part of “the science” we get to see fairly represents the work that has been done when the whole process is so highly politicized and ideological? How many grad students slogging away in labs or poking away at databases find things that never make it to publication because it would compromise the prevailing paradigm and their advisor’s funding (and don’t have the huevos that Zamora had to get her findings published anyway)? I feel pretty certain this doesn’t just happen in nutrition, but in nutrition it really matters to each of us, every day–and even more so to those who rely on government programs for food.
How did nutrition science become so politicized? Dietary Guidelines, I’m looking at you. When policy “chooses” a winner and a loser in a scientific controversy, things change. Science gets done differently. And when policy (dressed up as science) chooses a side in what we should/should not eat in order to prevent ostensibly preventable things like obesity and disease, well, all hell breaks loose. When we act like we “know” what foods cause/prevent disease, good health becomes entirely the responsibility of the individual. If you get fat or sick–no matter what else is going in your world or in your body–it’s your own damn fault.
How do we un-politicize nutrition science? This article from Daniel Sarewitz, “Science can’t solve it,” offers some clues. Although he’s focusing on new biotechnologies that have out-run our ethical frameworks for dealing with them, these remarks could just as well apply to diet-chronic disease science. He calls for discussions and deliberations that:
… could address questions about what is acceptable and what isn’t, about appropriate governance frameworks for research, and about the relative priority of different lines of study given ongoing and inevitable uncertainties and disagreements about risks and benefits.
If there’s one thing we’ve got in diet-chronic disease science, it is “ongoing and inevitable uncertainties.” It’s highly unlikely that science is going to solve those uncertainties anytime soon. As for ethical frameworks, we have never given serious consideration to the ethical implications–not to mention the outright absurdity–of subjecting everyone in our diverse population to a single dietary prescription designed to prevent all of the major chronic diseases (none of which have ever been established as primarily nutritional in nature).
Until we get to these kinds of discussion, the creators of the 2015 Dietary Guidelines ought to listen to what Paul Marantz had to say back in 2010:
When the evidence is murky, public health officials may best be served by exercising restraint, which is reflected by making no recommendation at all.
And when they don’t (cuz who can resist telling all those stupid Americans how to eat?), at the very least, we’ll all get a little smarter about “the science.” As @Ted_Underwood put it on Twitter:
A stubborn love of bacon just taught Americans the diff. between p-values & effect size better than 100 stats courses could.
Works for me.
Many thanks to Dr. Sarah Hallberg, without whom it would have taken me another 5 years to stumble across some of these articles.
*Run one PTA meeting and try to get a half-dozen fairly intelligent, well-educated adults to coordinate plans for a yard sale, and you’ll see what I mean. We can’t agree on whether used children’s books should be 50 cents or $1–figuring out whether to ruin the health of Americans by buying off the media or silencing the scientists would be beyond any possible reckoning.