Is It Time for the Dietary Guidelines to Die?
The 2015 Dietary Guidelines were officially released yesterday. Put out every five years, the guidelines urged Americans to limit salt intake to under 2,300 milligrams per day, consume less than ten percent of their calories from added sugar, and restrict saturated fat intake. They also suggested eating less red and processed meat. Unlike years past, the guidelines eased up on eggs, following research showing that dietary cholesterol isn't as bad as was once thought.
Overall, the new guidelines are a shift in the right direction -- slightly more science-based -- but the difference is minimal. The guidelines still mostly ignore growing evidence that low-carbohydrate diets can be just as, if not more, healthy as so-called "balanced" diets. They also continue to tout the notion that sodium intake needs to be limited, contrary to recent evidence that it probably doesn't.
For thirty-five years, the dietary guidelines have offered middling advice. The fact that they are slightly better is little consolation to the millions of Americans who've tried to follow them and have found themselves overweight and unhealthy.
"Americans in general have been following the nutrition advice that the... US Departments of Agriculture and Health and Human Services have been issuing for more than 40 years," a team of researchers reported last year in the journal Nutrition. "Consumption of fats has dropped from 45% to 34% with a corresponding increase in carbohydrate consumption from 39% to 51% of total caloric intake."
You know what's happened over that same time period. Obesity has skyrocketed to epidemic proportions. Of course, there's no way to tell if this is due to or in spite of the guidelines, but few would disagree that the guidelines have had little effect in curbing the rise in obesity.
That begs an important question: If the dietary guidelines are so ineffectual, why even have them? Is it time for the dietary guidelines to die?
Supporting this notion is the glaring fact that nutrition science is notoriously terrible: characterized by poorly conducted research, pervasive industry influence, and a diffuse sense of confirmation bias almost akin to religion. Asking a government-selected panel to distill generally pathetic evidence into a broad set of guidelines is like asking a two-year-old to nail Jello to a wall with a plastic play hammer.
Dr. James Hamblin over at The Atlantic offers a reasonable point to the contrary, however. "Everyone agrees that having more data in the realm of nutrition science would be ideal, but this cannot paralyze us from acting to the best of our knowledge."
But here, another problem arises: who gets to decide upon which knowledge to act? Every five years, that duty falls to the dozen or so members of an advisory committee, who effectively create the guidelines. Unfortunately, they are not required to list their potential conflicts of interest, unlike authors in the vast majority of scientific journals.
"A cursory investigation shows several such possible conflicts," Nina Teicholz reported in the British Medical Journal. "One member has received research funding from the California Walnut Commission and the Tree Nut Council, as well as vegetable oil giants Bunge and Unilever. Another has received more than $10 000 from Lluminari, which produces health related multimedia content for General Mills, PepsiCo, Stonyfield Farm, Newman’s Own, and 'other companies.'"
Past panels have also had links to the dairy industry, which might help explain why the guidelines have regularly recommended drinking three cups of milk per day, despite the fact that a sizeable portion of the U.S. population has trouble digesting lactose, the primary sugar in milk, and that the benefits of milk have long been overstated.
The panel is also bombarded by lobbyists from "MillerCoors to the US Dry Bean Council — all vying for prime space on MyPlate,'" Sheila Kaplan reported for STAT. "More than 220 people registered to lobby on the guidelines during 2015, with many more unregistered."
The ultimate aim of the dietary guidelines is just as noble today as it was when they were created back in 1980: to help Americans eat and live as healthy as possible. But it doesn't appear that the guidelines are working. Ultimately, the failing isn't theirs, but ours. Subject to intense political lobbying, and the whims of our inherent biases, the guidelines are doomed to an ideological bent. It might be best for individual citizens to take their nutrition into their own hands, rather than look to the government for guidance.