Have Nutrition Scientists Turned Into The Teacher From 'Peanuts'?

by Kristina Lewis, MD

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A recent poll conducted by Truven Health Analytics and National Public Radio got press coverage for its finding that the majority of surveyed Americans characterized their eating habits as “good, very good or excellent”. This was surprising given that more objective measures of our diets are generally pretty poor - the average Healthy Eating Index (HEI) score for Americans 2 years and older is 59, out of a possible 100 points! That’s not great, and certainly not consistent with the way these survey respondents viewed their eating habits. What did not make the headlines, but is perhaps of greater interest to the nutrition science community, were poll responses that suggest that many Americans completely missed some of the major changes in the 2015 Dietary Guidelines for Americans (DGA), despite the media hubbub that surrounded their publication.

The poll, conducted by phone or on the web for 3,007 participants between May 1-14, 2016 included several questions on dietary fat and foods high in cholesterol. The majority of those surveyed (74.4%) were unaware of the removal of limits on foods containing cholesterol from the updated DGA. Among those who were aware, over half (64.2%) said they had not changed their intake of “high cholesterol” foods based on the new DGA, and 14% had actually decreased their intake. When respondents were asked if they were generally confused about the amount and type of fats that make up a healthy diet, most indicated “no” (64.7%), although levels of confusion were highest in those  younger than 35 years old, of whom 44.9% were confused.

The results of this survey are certainly subject to limitations of its methodology, which is somewhat hard to assess with the available information on the surveyor’s website. For example, the wording of the survey questions was less than ideal in many cases and could have led to different interpretations by respondents. Additionally, there was no information provided on sampling strategy or whether they felt they got a group that was representative of the American public. Available co-variates were limited, probably due to brevity of the poll, and did not include any health-related data points such as weight status or chronic illnesses. The survey website highlights “statistically significant” responses in bold but does not specify which statistical test was used, the threshold for statistical significance, or what groups were being compared.

Despite the methodological limitations of this poll – which, in fairness, did not aim to be a peer-reviewed research study – it is interesting that most surveyed Americans were not remotely familiar with one of the most widely publicized aspects of the 2015 DGA. This may be reflective of the public’s fatigue with ever-changing recommendations of nutrition experts. Perhaps people are so tired of overhauling their diets every few years that they have just stopped listening? Or perhaps the guidelines were so vast that some of these changes simply didn’t register? Either way, it’s possible that the majority of Americans now think that they are eating healthy diets, report that they are not confused about topics such as dietary fat, and yet have apparently tuned out any updates from the nutrition science community. Moving forward, it will be important for experts to consider how to re-engage the public with this topic, streamline their messaging, and provide a clear justification for any changes in dietary recommendations (and this cannot just be “we got it wrong before”). Otherwise, all that Americans will hear when we speak is: “Wah wah wah, wah wah wah…..”