[Relationship of body composition measured by DEXA with lifestyle and satisfaction with body image in university students].

Introduction: body mass index (BMI) can under-diagnose overweight and obesity as it is a surrogate measure of central adiposity, making it necessary to define more adequate variables for its correct diagnosis. Objective: to compare the categorization of overweight and obesity according to the percentage of fat measured with dual-energy X-ray absorptiometry (DEXA) with the BMI and the Clínica Universidad de Navarra - Body Adiposity Estimator (CUN-BAE) formula, as well as their relationship with adherence to the Mediterranean diet, physical activity and satisfaction with body image. Subjects and methods: cross-sectional study conducted in 64 medical students. We determined weight, height, waist circumference, percentage of fat measured with DEXA, adherence to the Mediterranean diet, level of physical activity and degree of satisfaction with body image. Results: BMI underdiagnoses overweight with respect to the percentage of fat measured by DEXA while CUN-BAE has a good correlation. Percentage of fat is inversely associated with satisfaction with body image more strongly than the BMI. Conclusion: the limitations of BMI to diagnose excess body fat pose the need for new tools to distinguish patients with normal BMI whose percentage of body fat is high. It would be useful to assess whether the use of a questionnaire of satisfaction with body image in people classified as normal weight could distinguish individuals with a higher probability of excess of fat, and thus, employ more accurate study methods in this group.