Wednesday, August 28, 2019

Retrospective #193: “We never changed our mind,” the “scientist” said.

The Los Angeles Times headlined, “High-protein diets: Bad for the middle-aged, good for the elderly.” The piece concludes, “But over 20 years of research linking heavy protein consumption to diseases of aging, eventually to higher IGF-1 levels, he said, ‘we never changed our mind’: Americans’ protein-packed diets ‘are hurting them in a major way.’” This “research” is just another example of “sort-of-science,” an aphorism I attribute to Gary Taubes.
The piece, and the journal Cell Metabolism where the “research” originally appeared, are complicit in this “sort-of-science.” Quoting from The Nutrition Debate #192, and referring to Taubes’s New York Times op-ed:
“The scientific method requires that a hypothesis be rigorously tested, with a skeptical bias, and… the ‘proof’ replicated. Such clinical trials to ‘prove’ that dietary fat caused heart disease, were necessary, scientists acknowledged, but could not be undertaken, for reasons he gives. ‘Since then,’ Taubes wrote, ‘advice to restrict fat and avoid saturated fat has been based on supposition about what would have happened had such trials been done, not on the trials themselves.’
Taubes continues, ‘Nutritionists have adjusted to this reality by accepting a lower standard of evidence on what they’ll believe to be true. One lesson of science, though, is that if the best you can do isn’t good enough to establish reliable knowledge, first acknowledge it – relentless honesty about what can and cannot be extrapolated from data is another core principle of science – and then do more, or do something else. We have a field of sort-of-science in which hypotheses are treated as facts because they’re too hard or expensive to test.’”
The problem with this “research,” is that it is from a “large-population study” (“20 years of research”) and the findings are all “supposition about what would have happened” if a randomized controlled trial of the subject population had been done. The evidence of this will be clear to the discerning reader. Quoting from #192 again:
“This research is of the kind called ‘observational studies,’ wherein what the researchers do is ‘observe populations for decades, document what people eat and what illnesses beset them, and then assume that the associations they observe between diet and disease are indeed causal,’ quoting from Taubes’s Op-Ed. Taubes continues: ‘– that if people who eat copious vegetables, for instance, live longer than those who don’t, it’s the vegetables that cause the effect of a longer life. And maybe they do, but there’s no way to know without experimental trials to test the hypothesis.’”
The associations that emerge from these studies used to be known as “hypothesis generating data, [since] an association tells us only that two things changed together in time, not that one caused the other. So, associations generate hypotheses of causality that then have to be tested. But this hypothesis-generating caveat has been dropped as researchers studying nutrition have decided that this is the best they can do,” Taubes concludes, kindly.
I would not be so kind. I would conclude, cynically, that the “scientists” (and the media) have another agenda: in this case, to push a plant-based diet. In the LATimes piece it is patently transparent: “But the source of the protein mattered a great deal: for those whose sources of protein were heavily plant-based, nuts and legumes – the increased risk of dying of cancer declined and the increased risk of all-cause mortality disappeared altogether.”
The reporter, in case you questioned her objectivity (Is she vegan?), extends the “associations” of the researcher’s “sort-of-science,” piling on with this “observation”: “The findings of Longo’s team are in line with mounting research on the hazards of heavy consumption of red meats and the protective effects of plant-based nutrients.”
So, where does all this agenda-based science lead us? To confusion, for the uninitiated, which is most of the health-news-consuming public. Advocacy science is not science at all. “Studies of hypothesis-generating data produce more hypotheses, as they should,” Taubes says. But the public suffers, asking the perennial question, “Whom am I to believe?” For me, when I browse the science news and journal articles, and digests of so-called “science designed for the medical profession,” I take such observational studies with a heavy dose of salt (which I like).
Then to nutrition scientists Taubes says, “We’re going to have to stop believing we know the answer, and challenge ourselves to come up with trials that do a better job of testing our beliefs.” In other words, leave your mind open, rather than “never changing” it, as this study author had and said. I’m doing my best to keep an open mind. 

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