Extreme under‐reporting of body weight by young adults with obesity: relation to social desirability

OBJECTIVE: The objective of this study was to determine whether there is an association between under‐reporting of body weight and social desirability as is found with self‐reports of energy intake. METHODS: Twenty‐seven lean individuals (mean body mass index ± standard deviation = 21.6 ± 2.0 kg m(−2)) and 26 individuals with obesity (mean body mass index = 35.4 ± 4.8 kg m(−2)) were e‐mailed a questionnaire on which they had to state their body weight and conduct a home food inventory. The next day, research team members went to their homes to weigh the participants, conduct their own food inventory and administer the Marlowe–Crowne scale for social desirability. RESULTS: Among individuals with obesity, lower social desirability scores were associated with a greater degree of under‐reporting body weight (r = +0.48, p < 0.02). Among lean individuals, the correlation was negative but statistically non‐significant (p = −0.22, p > 0.10). Nine individuals with obesity were extreme under‐reporters (2.27 kg or more), and eight of these had social desirability scores in the bottom half of the Marlowe–Crowne scale (p < 0.01). Six under‐reported on the home food inventory by three or more items. CONCLUSIONS: Individuals with obesity and low social desirability scores are more likely than others to be extreme under‐reporters of body weight, possibly due to a lack of awareness of their own weight.