Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically‐scaled

OBJECTIVE: The aim of this study was to assess the extent of misreporting in obese and nonobese adults on an absolute, ratio‐scaled, and allometrically‐scaled basis. METHOD: Self‐reported daily energy intake (EI) was compared with total energy expenditure (TEE) in 221 adults (106 male, 115 female; age 53 ± 17 years, stature 1.68 ± 0.09 m, mass 79.8 ± 17.2 kg) who participated in a doubly‐labeled water (DLW) subsection of 2013–2015 National Diet and Nutrition Survey. Data were log transformed and expressed as absolute values, according to simple ratio‐standards (per kg body mass) and adjusted for body mass allometrically. Absolute and ratio‐scaled misreporting were examined using full‐factorial General Linear Models with repeated measures of the natural logarithms of TEE or EI as the within‐subjects factor. The natural logarithm of body mass was included as a covariate in the allometric method. The categorical variables of gender, age, obesity, and physical activity level (PAL) were the between‐factor variables. RESULTS: On an absolute‐basis, self‐reported EI (2759 ± 590 kcal·d(−1)) was significantly lower than TEE measured by DLW (2759 ± 590 kcal·d(−1): F(1,205) = 598.81, p < .001, η ( p ) (2) =0.75). We identified significantly greater underreporting in individuals with an obese BMI (F(1,205) = 29.01, p <.001, η ( p ) (2) =0.12), in more active individuals (PAL > 1.75; F(1,205) = 34.15, p <.001, η ( p ) (2) =0.14) and in younger individuals (≤55 years; F(1,205) = 14.82, p < .001, η ( p ) (2) =0.07), which are all categories with higher energy needs. Ratio‐scaling data reduced the effect sizes. Allometric‐scaling removed the effect of body mass (F(1,205) =0.02, p = 0.887, η ( p ) (2) =0.00). CONCLUSION: In weight‐stable adults, obese individuals do not underreport dietary intake to a greater extent than nonobese individuals. These results contradict previous research demonstrating that obesity is associated with a greater degree of underreporting.