Validity of U.S. nutritional surveillance:National Health and Nutrition Examination Survey caloric energy intake data, 1971-2010.
Level 4 - case-series / case-control
Repeated cross-sectional survey data analysis comparing reported intake against physiological estimates.
PubMed 24130784 · doi:10.1371/journal.pone.0076632
What was done
Validity of caloric intake data from 63,362 participants (28,993 men and 34,369 women aged 20 to 74 years) across NHANES I (1971–1974) through NHANES 2009–2010 was evaluated. Physiological credibility was assessed using the ratio of reported energy intake (rEI) to estimated basal metabolic rate (BMR), and by calculating disparity values subtracting estimated total energy expenditure (TEE) from reported energy intake (rEI - TEE).
What was found
Historical mean rEI/BMR ratios were 1.31 (95% CI: 1.30 to 1.32) for men and 1.19 (95% CI: 1.18 to 1.20) for women. Historical mean disparity values (rEI - TEE) were -281 kcal/day (95% CI: -299 to -264) for men and -365 kcal/day (95% CI: -378 to -351) for women, indicating significant underreporting. Disparities were greatest in obese participants (-716 kcal/day in men, -856 kcal/day in women). Overall, energy intake data were physiologically implausible for 67.3% of women and 58.7% of men across the 39-year period. Protocol updates after NHANES II led to artifactual increases in rEI with only trivial improvements in validity.
Why it matters
This analysis shows that self-reported caloric intake in major U.S. nutritional surveillance data is largely physiologically non-credible, limiting its utility for establishing diet-disease relationships or public health nutrition policy.
Limits
Energy expenditure and basal metabolic rate values were estimated using predictive equations rather than directly measured via objective biomarkers (such as doubly labeled water). The analysis only evaluated total energy intake rather than macronutrient or micronutrient composition.
Cited by
- context Self-reported dietary intake data estimates average caloric intake in Americans at approximately 2,400 to 2,500 calories per day.