Underreporting of Habitual Food Intake Is Explained by Undereating in Highly Motivated Lean Women

Open Access
Publisher Website
Google Scholar
Abstract
Underreporting of habitual food intake can be explained by underrecording and/or undereating. This study was designed to discriminate between the two errors mentioned, by measuring energy and water balance. Twenty-four lean female dieticians were recruited as subjects. Energy intake and water intake were measured for 1 wk with a weighed dietary record. Energy expenditure was estimated from measurements of resting metabolic rate, and measured physical activity with a triaxial accelerometer for movement registration. Water loss was estimated with deuterium-labeled water. Energy balance was determined by measuring the change in body mass over a nonrecording week (preceding the recording week) and over the recording week. Mean energy and water intake were 8.5 ± 1.0 MJ/d and 2.3 ± 0.5 L/d. The change in body mass in the nonrecording week was 0.1 ± 0.6 kg and in the recording week −0.6 ± 0.8 kg (paired t test; P = 0.02), indicating 16% undereating. Recorded water intake plus calculated metabolic water closely matched measured water loss (r = 0.93; P = 0.0001), which indicated a high recording precision. In conclusion, in the studied group of highly motivated lean women, there was 16% underreporting of habitual food intake, which could be explained by undereating.