GOOD QUESTION: The scientific report guiding the US dietary guidelines: is it scientific?

In its 2015 report the committee stated that . . . for more than 70% of the topics, . . . it relied on systematic reviews by external professional associations, almost exclusively the American Heart Association (AHA) and the American College of Cardiology (ACC), or conducted an hoc examination of the scientific literature without well defined systematic criteria for how studies or outside review papers were identified, selected, or evaluated. . . .

Potential conflicts of interest include, for instance, decades of support from vegetable oil manufacturers, whose products the AHA has long promoted for cardiovascular health. This reliance on industry backed groups clearly undermines the credibility of the government report. . . .

Papers on saturated fats published since 2010 were covered by the committee’s ad hoc review, which did not use a systematic method to select or evaluate studies. . . . Three meta-analyses concluded that saturated fats did not increase cardiovascular mortality, but the committee downplays these findings. And two other included meta-analyses had mixed results . . . Despite this conflicting evidence, however, the committee’s report concludes that the evidence linking consumption of saturated fats to cardiovascular disease is “strong.” . . .

Another important topic that was insufficiently reviewed is the efficacy of low carbohydrate diets. . . .

Because the guidelines have obviously not led to better health, . . . there has been a need to find new strategies to tackle nutrition related diseases. . . . The committee’s most significant shift, which began in 2010, . . . has been to redouble its efforts towards emphasizing a plant based diet. This can be seen in a number of ways in the 2015 report, none of which is supported by strong evidence.