Child obesity figures have increased in recent decades, affecting more than 100 million children around the world (1). In addition to the already known damages that children's health can have (for example, increasing the incidence of insulin resistance, hypercholesterolemia or hypertension), it has been observed that obesity could negatively affect academic performance, although Evidence in this regard does not seem unanimous. In fact, a systematic review concluded that approximately half of the studies that have analyzed this relationship does not find a clear association between a higher body mass index (BMI) and a worse academic performance (2).

In this sense, it is possible to think that the physical form could be the determining factor that modulates the influence of body weight on academic performance. For example, it has been observed that an optimal cardiorespiratory fitness is able to attenuate the negative effects of obesity on cardiovascular health, which has been called as the 'fat but fit' paradox (English, “obese” but in form ) (3). In addition, different systematic reviews and meta-analysis have shown that a greater physical form is associated with better academic performance (4.5). But can a good physical form avoid the negative effects of obesity?

To answer this question, in a recent study (6) that we have published in the prestigious International Journal of Obesity magazine together with Dr. Óscar Martínez de Quel we analyzed 188 students of an institute (average age of ~ 14 years). The physical form of students with different tests to determine their strength, cardiorespiratory fitness, muscle power, coordination and flexibility, and also determined their BMIs to categorize them in Normapeso (BMI <25 kg/m ² ) or overweight/obesity ( > 25 kg/m ² ). When analyzing their average notes of all the subjects they were studying, we observe that different markers of physical form such as cardiorespiratory fitness, lower train power, sprint capacity or flexibility were directly associated with better academic performance. In addition, students with Normopese presented better notes than those overweight or obesity. Interestingly, by dividing the students into four sub-groups attending their physical form and their weight category (in good shape or in low form, and with normopese or overweight/obesity), we observe that students with good physical and normopese form They took better notes than students at the other end, that is, with low physical form and overweight or obesity. However, within the students with overweight or obesity, those who had good physical form did not get worse notes than those who had Normopeso. Having a good physical form countered the effects of obesity on academic performance.

These results therefore show the importance of maintaining a good physical form to improve academic performance, charging special relevance in the case of overweight or obesity children. In fact, a high BMI has been associated with a worse cortical development in children, as a study published in the prestigious Jama Pediatrics magazine that included more than 3000 children (7). On the contrary, another study published by Spanish authors showed that a good physical form is associated with a greater volume of gray matter in the brain in overweight or obesity, this adaptation related to greater academic performance (8). The implementation of strategies aimed at improving the physical form of children and adolescents must therefore be a priority to avoid health problems and to improve cognitive performance.

References:

1. Bentham J, Di Cesare M, Bilano V, Bixby H, Zhou B, Stevens Ga, et al. Worldwide Trends in Body-Mass Index, Underweight, Overweight, and Obesity from 1975 to 2016: A Poold Analysis of 2416 Population-Based Measurement Studies in 128 · 9 Million Children, Adolescents, and Adults. Lancet 2017; 390 (10113): 2627–42. 

2. Santana CCA, Hill Jo, Azevedo LB, Gunnarsdottir T, Prado WL. The Association Between Obesity and Academic Performance in Youth: A Systematic Review. OBES Rev. 2017/07/25. 2017 Oct; 18 (10): 1191–9. 

3. Ortega FB, Ruiz Jr, Labayen I, Lavie CJ, Blair Sn. The Fat But Fit Paradox: What We Know and Don't Know About It. BR J Sports Med. 2018; 52 (3): 151–3. 

4. Marques A, Santos da, Hillman Ch, Sardinha Lb. How Does Academic Achievement Relate To CardiorespiRary Fitness, Self-Reported Physical Activity and Objectively Reported Physical Activity: A Systematic Review in Children and Adolescents Anged 6-18 Years. BR J Sports Med. 2018; 52 (16): 1039. 

5. ALVAREZ-BUENO C, PESCE C, CAVERO-REDONDO I, SANCHEZ-LOPEZ M, GARRIDO-MIGUEL M, MARTINEZ-VIZCAINO V. ACADEMIC ACHIELVEMENT AND PHYSICAL ACTIVITY: A META-ANALYSIS. Pediatrics 2020; 140 (6). 

6. Martínez-Zamora M, Valenzuela P, Pinto-Escalona T, Martínez-de-which O. The "Fat But Fit" Paradox in the Academic Context: Relationship Between Physical Fitness and Weight Status with Adolescents' Academic Achievement. Int j obes. 2020; in press. 

7. Laurent JS, Watts R, Adise S, Allgaier N, Chaarani B, Garavan H, et al. Associations Among Body Mass Index, Cortical Thickness, and Executive Function in Children. Jama Pediatr. 2020; 174 (2): 170–7. 

8. Esteban-Cornejo I, Cadenas-Sanchez C, Contreras-Rodriguez O, Verdejo-Roman J, Mora-Gonzalez J, Migueles JH, et al. A Whole Brain Volumetric Approach in Overweight/Obese Children: Examination the Association with Different Physical Fitness Components and Academic Performance. The Activbrains Project. Neuroimage 2017; 159 (July): 346–54.