The results of a recent study suggest that data collected from the National Health and Nutrition Examination Survey (NHANES), used to create dietary guidelines and public health policies, may be inaccurate.
For the NHANES, adults aged 20 to 74 years are asked during an interview to recall what they ate during the past 24 hours. Using information from food and nutrient databases, caloric values are estimated based on interview responses. The current study, published online on October 9, 2013, in PLOS One, assessed the validity of this caloric intake data collected from the NHANES I, conducted from 1971 to 1974, through NHANES 2010. The researchers compared the participants’ self-reported caloric intake with their estimated energy expenditure, based on height, weight, age, and gender.
The results indicated that caloric intake data for 67.3% of women and 58.7% of men were not physiologically plausible, suggesting that many survey participants significantly underreport the amount of calories they eat in 1 day. Overweight and obese women were the most likely to underreport their caloric intake.
“Interventions emphasizing the importance of ‘healthy’ behaviors may lead to increased misreporting as participants alter their reports to reflect the adoption of the ‘healthier’ behaviors independent of actual behavior change,” write the authors.