Ideal body shape in young Japanese women and assessment of excessive leanness based on allometry

The present study is aimed to clarify the degree of leanness desired by contemporary young Japanese women using questionnaires and to use allometry to define the body weight boundary between the excessively lean and the others for a given height. Questionnaires on ideal body shape were distributed to female college students living in Akita and the suburbs of Tokyo. Data for 578 respondents, aged 18 to 21 years-old, were analyzed. The questionnaire asked the subjects to report their current and ideal body shape and to make a qualitative self-assessment of their weight. On average, the perceived ideal weight was 5.2 kg lower than the current weight. The results also revealed that young women have a tendency to misunderstand their body shape and to regard themselves as heavier than they really were. Meanwhile, we defined leanness as a state of insufficient lean body mass (LBM, kg) in relation to height (Ht, cm). Allometric equation of LBM on Ht and the standard error of estimate (SEE) were calculated as LBM=3.87 x 10(-3) x Ht(1.826) and 1.09, respectively. The LBM boundary between the excessively lean and the others was determined using these values according to a statistical procedure comparing normal and abnormal values. The corresponding total body weight was estimated from the boundary LBM in the literature. Subsequently the body weight boundary for each height was tabulated in order to make young women reconsider weight control. The subjects were asked to assess the body weight boundary for their own height. The boundary values were found to be consistent with the sense of the subjects.