March 6 2014
What are Americans to make of the continued flip flopping on health and diet information?
I imagine most people begin tuning it all out (I tend to do this). Yet, surely some still pay attention and for those few people, it has to be exhausting trying to keep track of it all. Consider the mixed messages surrounding beef (I’ve written about the topic here, here and here).
Americans are advised to limit carbohydrates in favor of protein rich diets and are told beef is a healthy protein source. And just when they have integrated beef and other proteins into their diets, a new study emerges, which creates fear, uncertainty and doubt. The newest study on beef, published in the Journal of the American Medical Association (JAMA), does just that and is generating a ton of scary headlines. The study finds:
...greater consumption of unprocessed and processed red meats is associated with higher mortality risk. Compared with red meat, other dietary components, such as fish, poultry, nuts, legumes, low-fat dairy products, and whole grains, were associated with lower risk. These results indicate that replacement of red meat with alternative healthy dietary components may lower the mortality risk.
Geeze. Wow. Time to start eating more Portobello burgers, right?
Heck no! Instead of removing beef from your shopping list, reassure yourself by reading Zoe Williams analysis of the JAMA study in The Guardian, where she explains that the beef = cancer connection isn't so clear-cut. She writes:
But the overriding fact in all this is that this new study is wrong: the US data set from which it is drawn is fatally flawed and the link between protein and premature death is simply not demonstrable from this evidence. Jack Winkler, former professor of nutrition policy at Metropolitan University, explains: "They did a correlation between the national diet survey in the United States (NHANES), and some data on death by disease. They linked it up, then alleged that protein caused death. Now, NHANES suffers from what all diet surveys suffer, namely: you ask people what they eat and what you get back is lies. People respond normatively. They put themselves in the best possible light. They're not harmful, deceitful lies. In the case of the British survey, people underreport how much they eat by 25% and adolescents by 30%. Underreporting they call it, but in plain English, it's lies."
A study has just been published on what's wrong with NHANES, which concludes: "Across the 39-year history of the NHANES, EI [Employment Insurance] data on the majority of respondents (67.3% of women and 58.7% of men) was not physiologically plausible." In plain English, if they really ate what they said they'd eaten, they would no longer be alive. In two-thirds of cases.
I also advise you to consider another study, which somewhat hilariously, examines the capriciousness of studies on nutrition...that's right, it's a study on studies (h/t Trevor Butterworth, who just wrote a fascinating piece on biased scientific studies in the Harvard Business Review).
Jokes aside, examining the legitimacy of studies based on self-reported data is critical because it shows that when people self-report, more often than not, they lie. That’s right…cheese doodle, Venti Mocha Latte, happy hour attending, gym skipping, Whopper and fry-eating Americans sometimes lie about their eating habits. It's understandable. People give aspirational answers. They don't want to admit their bad habits so they fudge the data.
This may seem harmless; until research papers, like the JAMA beef study, start feeding the food nannies that are intent on spreading misinformation about cancer and beef consumption.