Objective: There are powerful social and psychological motivators that oblige a high proportion of women to restrict their energy intake for purely aesthetic reasons. The purpose of this research was to assess the relationships between concern regarding body weight and energy balance in a group of female university students from Madrid, Spain, with respect to differences in body mass index (BMI).
Design: 126 subjects completed a questionnaire asking if they were happy with their body weight, if they considered themselves fat, and if they would like to lose some weight. Energy intake was measured by means of a 7-day food record. Food intake was recorded by weight, except for that consumed away from home which was recorded using traditional household quantities. A comparison of energy intake and estimated energy expenditure was performed, using equations proposed by the World Health Organization (WHO), to provide a measure of the under- or overestimation of intake.
Results: All subjects with BMI > or = 25 kg/m2 (6.2% of the total) described themselves as fat. 71.4% had, at some time, followed a weight-reduction diet. However, even among subjects with BMI < 20 kg/m2 (28.4% of the total), 2.9% thought themselves fat and 17.1% had at some time followed a slimming diet. This shows excessive concern over losing weight in some women. Estimated energy expenditure was similar to energy intake in subjects with BMI < 20 kg/m2. However, as BMI rose (with a corresponding increase in theoretical energy expenditure), the reported energy intake decreased. It is therefore likely that underestimation of energy intake increased with BMI (r = 0.4498).
Conclusion: These results indicate that a large percentage of the women studied would like to lose weight until they reach, or indeed exceed, the lower limit of the acceptable normal range. This could be a danger to their health. Underestimation of energy intake was found to increase with BMI, a phenomenon that should be kept in mind when designing diet studies.