Self-perception of weight in school-age children from Piedras Negras, Coahuila, Mexico

Background: The prevalence of overweight and obesity has increased worldwide. In this context, the lack of awareness of excess weight among overweight and obese children is a public health concern that needs to be explored in the Northern border of Mexico. Methods: Body mass index (BMI) was calculated from children from third to sixth grades of basic education. The Children's Body Image Scale was applied to evaluate perceived and ideal BMI comparing against calculated BMI. We also analyzed the frequency of accurate perceivers of actual weight and discrepancy of ideal weight against calculated BMI. Results: We studied 155 children (43.8% were female) with a mean age of 10.2 years. Accuracy prevalence of BMI perceived respect to calculated BMI was 59.4%. Discrepancy prevalence of ideal BMI respect to calculated BMI was 44.4%. Comparison of perceived BMI respect to calculated BMI showed an overestimation on low weight category (33%) and subestimations in categories of normal weight (12.4%), overweight (85%) and obesity (81.6%). Comparison of ideal BMI respect to calculated BMI showed an absolute overestimation of low weight and underestimations in categories of normal weight, overweight and obesity of 5.6%, 100%, and 97.4%, respectively. Conclusions: The results of this work showed a consistent underestimation of children's body weight, particularly among those classified in categories of overweight and obesity in a demographic context in which the prevalence of both categories was of 38% in this study.