Cross-sectional study of the differences between measured, perceived and desired body size and their relations with self-perceived health in young adults: The Tromsø Study - Fit Futures 2.

Aims: The aim of this study was to explore the relationships between measured body size (body mass index (BMI)), perceived body size, weight change wishes and self-perceived health in young adults.

Methods: The participants were recruited from a school-based population study in Norway, the Tromsø Study: Fit Futures 2, carried out in 2012-2013. A total of 629 young women and men (aged 18-23 years) reported on the main variables. The data were collected through weight and height measurements and questionnaires. The analyses were performed with descriptive statistics, the χ test and Student's t-test.

Results: A total of 20% of the women and 28% of the men were overweight or obese. There were considerable discrepancies between the measured BMI and perceived body size in both sexes. A substantial number of participants wanted to change their weight. Among the 174 women who reported that they were trying to lose weight, as many as 57 (32.8%) had a low normal weight (BMI 18.5-21.9 kg/m). Correspondingly, among the 66 men who reported that they wanted to gain weight, as many as 19 (28.8%) had a high normal weight (BMI 22-24.9 kg/m). We found no relation between body size perceptions, weight change wishes and self-perceived health.

Conclusions: Discrepancies between measured and perceived body size and weight change wishes are common findings in young adults. The lack of relation with self-perceived health found in our study is surprising and not easy to interpret. To gain more knowledge about these matters, further research, including both qualitative and quantitative studies, is needed.