Any study that depends on self-reporting, especially self-reporting on things like how much food they eat, can’t be assumed to be accurate:
Four decades of nutrition research funded by the Centers for Disease Control and Prevention (CDC) may be invalid because the method used to collect the data was seriously flawed, according to a new study by the Arnold School of Public Health at the University of South Carolina.
The study, led by Arnold School exercise scientist and epidemiologist Edward Archer, has demonstrated significant limitations in the measurement protocols used in the National Health and Nutrition Examination Survey (NHANES). The findings, published in PLOS ONE (The Public Library of Science), reveal that a majority of the nutrition data collected by the NHANES are not “physiologically credible,” Archer said.
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The study examined data from 28,993 men and 34,369 women, 20 to 74 years old, from NHANES I (1971 — 1974) through NHANES (2009 — 2010), and looked at the caloric intake of the participants and their energy expenditure, predicted by height, weight, age and sex. The results show that — based on the self-reported recall of food and beverages — the vast majority of the NHANES data “are physiologically implausible, and therefore invalid,” Archer said.
In other words, the “calories in” reported by participants and the “calories out,” don’t add up and it would be impossible to survive on most of the reported energy intakes. This misreporting of energy intake varied among participants, and was greatest in obese men and women who underreported their intake by an average 25 percent and 41 percent (i.e., 716 and 856 Calories per-day respectively).
