The New England Journal of Medicine (NEJM) is the oldest continuously published medical periodical, having been first published in 1812. It is also the most widely read, cited, and influential general medical periodical in the world. As such, papers published in the NEJM tend to be widely read and carry a fair amount of weight.
Recently, a perspective (editorial) and original article were published in the October 27th issue of the NEJM that we feel deserve some discussion. Today we’ll discuss the perspective (link to full text here).
Two physicians from the Department of Nutrition at the Havard School of Public Health have written the journal about the revised 2010 U.S. Dietary Guidelines that were released earlier this year by the USDA. You might recall a previous post on this blog in which we summarized our thoughts regarding the new guidelines. The perspective that the authors offer in the journal is not much different from our take on the new guidelines and offers the following five points (taken verbatim from the paper) that we feel are important to highlight (emphasis added in bold).
1. “The 35% limit on calories from fat, which remains embedded deep within the document, may inadvertently undermine the quality of federally funded nutrition programs.”
“For example, the prevailing limit on total fat consumption to 35% of calories derives from a 2002 report based on evidence purportedly linking the percentage of energy in the diet from fat with obesity. However, this relationship has since been refuted in many well-controlled, prospective, observational studies and clinical trials that show little independent effect of dietary fat on body weight. Nevertheless, the diets of millions of Americans who participate in school-lunch and nutrition-assistance programs remain loaded with refined carbohydrates in an effort to reduce fat as a proportion of total calories, whereas the focus should be on replacing trans and saturated fats with healthier fat.”
2. “The guidelines continue to recommend three daily servings of dairy products, despite a lack of evidence that dairy intake protects against bone fractures and probable or possible links to prostate and ovarian cancers.”
3. “Although eating of whole grains is encouraged, half of recommended grain intake may be in the form of refined carbohydrates, which provide many unneeded calories and cause adverse metabolic consequences. Furthermore, the quality of carbohydrates, as characterized by their glycemic index, is dismissed as unimportant, whereas we believe the evidence strongly suggests the opposite.”
4. “Deep in the guidelines, diligent readers can find a recommendation to limit sugar-sweetened beverages, but these products deserve front page attention as the single greatest source of calories in the U.S. diet and an important contributor to obesity, diabetes, heart disease, gout, and dental caries. This imbalance — foods whose intake should be increased are described clearly, but those whose intake should be reduced are hidden in fine print or obscure acronyms — typifies USDA and DHHS guidelines.”
5. “A focus on foods, rather than individual nutrients, is particularly important because the relationship between diet and chronic disease cannot be adequately predicted from the effects of individual nutrients, and because people choose foods, not nutrients, when deciding what to eat.”
In summary, the authors reiterate that, “The original Food Guide Pyramid, which encouraged substituting grain products for dietary fat (irrespective of their nutritional quality), may have inadvertently contributed to epidemics of metabolic syndrome and related chronic diseases by increasing refined-starch consumption.” To proponents of a paleo or ancestral way of eating, this is no surprise, but for most of the public who have been led to believe that whole grains and low fat diets pave the path to great health, we fear that they have been led astray. Most people know that rates of obesity in the U.S. have been rising, but those same people forget or are unaware that the fat content of the U.S. diet (on average) has decreased in recent years. Some fats (e.g., trans fats) are no good for you, but fat in and of itself is not the enemy here.
Lastly, the authors conclude that, “Although important progress has been made, Americans will need to rely on multiple sources for information about diet and health until the process of formulating the guidelines is fundamentally improved.” Dear readers, we hope to serve as one of those important, evidence-based sources of information about diet and health for you.
Now get out to your farmers markets and have a great weekend!
Dan’s Plan