When it comes to reporting on the latest diet science news, it’s hard to know who to trust. Reporters covering the diet science beat seldom display much in the way of scientific acumen or plain curiosity. Their editors don’t seem to care as long as they can illustrate the stories with close-ups of pretty girls putting things in their mouths.
1. The Great Chocolate Con
Can eating dark chocolate every day help help you lose weight?
Yes, according to a study published earlier this year and widely — and uncritically — reported by the media.
The claim was that adding a chocolate bar a day to a low-carb diet helped subjects lose weight 10% faster. Turns out, the study was deliberately and seriously flawed, as its chief perpetrator, John Bohannon, admits in an article for io9: “I Fooled Millions . . .” The clinical trial involved only 15 subjects, while measuring a slew of variables (18 of them) for each, so odds were that some statistically significant but scientifically dubious association would emerge. Bohannon writes that the “study design is a recipe for false positives.” Other research red-flags were included. Nevertheless, the study quickly found a home in a journal, and then reporters covering the “diet science beat” ate it up, writing their stories straight from the press release with at best some perfunctory fact-checking. It’s a depressingly typical approach. As Bohannon concludes, “the diet science beat is . . . science. You have to know how to read a scientific paper—and actually bother to do it. For far too long, the people who cover this beat have treated it like gossip. . . .”
The next short-take illustrates just such a shallow, gossipy approach to diet science news.
2. Your Mouse on a High Carb Diet
“Forget calories and eat carbohdrates for a longer life” a headline on the Sydney Morning Herald web site urges readers. Below the headline is a close-up photograph of a healthy, attractive, smiling young woman lifting a forkful of fettuccine to her mouth. (Bohannon noted that the preferred way of illustrating the stories about his bogus study was with “vaguely pornographic images of women eating chocolate.”) The implication of the top-matter is that eating such carb-heavy food as pasta will help a human being to live longer. But the article is another example of superficial and misleading diet science reporting. The study being reported on focused on mice, not humans. It found that mice that were fed a low-protein high-carb diet, or a greatly reduced calorie diet, tended to live longer than mice that were fed a high-protein low-carb diet.
A number of questions occur to me that apparently did not occur to the Sydney Morning Herald reporter. For example, a reasonable question to ask is how comparable the normal diets and digestive systems of mice are to those of humans. There’s nothing to indicate such a question was asked. Another question I have is whether a low-carb high-fat diet was tested. Again, the article doesn’t say. I’m also curious about why the researchers followed the subject mice for a mere eight weeks — the equivalent of two human years. Is that long enough to draw firm conclusions about longevity in relation to diet? Perhaps it is, by some arcane mathematical reasoning, but if I were the reporter, I’d at least raise the question. In fact, I’d raise it loudly. And finally, did any of the mice eat fettuccine alfredo? Is that the kind of carbohydrate-rich food that will supposedly prolong our lives?
If I thought this was an important study, I’d go find the answers to those questions. But I don’t think a single mouse-study matters much in the grand scheme of things. I think shoddy reporting on the diet science beat matters a lot more.