Introduction/Objective Adolescence is a critical period for the development of obesity. Obesity arises from a complex interaction between several factors, which are not yet fully understood. Therefore, the purpose of this review was to identify and assess the peer-reviewed scientific literature on the behavioral, contextual and biological factors associated with obesity in adolescents. Methods PubMed and Scopus were systematically searched to identify prospective cohort studies concerning the relation between behavioral, contextual and biological factors and obesity in adolescents aged 10 to 18 years. Results 40 studies published between the year 2000 and 2018 were included. A positive consistent association between genetic factors and obesity during adolescence was found. Also, there is evidence to support the association between socioeconomic status and obesity. There was conflicting evidence for the contribution of dietary intake, physical activity, sedentary behavior, sleep, food store environment, school food environment. For the remaining factors no associations were found, or no conclusions could be drawn due to the limited number of studies identified. Conclusions Further prospective studies that assess multiple obesity determinants simultaneously and use state-of-art measures are warranted to aid in the development of effective strategies and interventions to prevent obesity during adolescence.

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Effective obesity interventions in adolescent populations have been identified as an immediate priority action to stem the increasing prevalence of adult obesity. The purpose of this meta-analysis was to make a quantitative analysis of the impact of school-based interventions on body mass index during adolescence. Studies were retrieved from PubMed, Scopus, Science Direct and Web of Science databases. Results were pooled using a random-effects model with 95% confidence interval considered statistically significant. Of the 18 798 possible relevant articles identified, 12 articles were included in this meta-analysis. The global result showed a low magnitude effect, though it was statistically significant (N = 14 428), global e.s. = −0.055, P = 0.004 (95% CI = −0.092, −0.017). Heterogeneity was low among the studies (I2 = 9.017%). The funnel plot showed no evidence of publication bias. The rank-correlation test of Begg (P = 0.45641) and Egger’s regression (P = 0.19459) confirmed the absence of bias. This meta-analysis reported a significant effect favoring the interventions; however, future research are needed since the reported the evidence was of low magnitude, with the studies following a substantial range of approaches and mostly had a modest methodological quality.

Background Obesity prevalence has been rising worldwide and currently is one of the most serious public health problems. Nutrition literacy is important to the development of healthier habits that could help prevent and stem obesity and overweight. The aim of this study was to evaluate the impact of using a multimedia web platform to provide nutrition education to Portuguese adolescents. Methods The intervention consisted in a two-week period in which students (n = 1291) had access to an interactive multimedia web platform with nutritional content, and designed for a self-paced learning experience. Students completed a knowledge questionnaire at baseline and immediately after the end of the intervention. Results The results obtained revealed that 85.8% of the students increased their nutrition knowledge. No gender differences were observed post-intervention. There were significant differences in the knowledge acquisition regarding age (P < 0.001). The baseline knowledge seemed to influence the learning process. Conclusions Overall, the intervention had a positive impact. The preliminary results observed will be important for the improvement of the intervention, though they need to be confirmed by further research. Nevertheless, it is safe to say that technology-based assets can be important tools to incorporate and complement health-related interventions in schools.

Obesity has become a major global health challenge and it is a risk factor for the development of several comorbid conditions. Additionally, obesity has considerable economic consequences. Obesity is a multifactorial condition that arises from independent influences of genetic and social-environmental factors on food intake and physical activity. It has been difficult to establish clear associations between weight status and the intake of single foods or food groups. In most people, the predisposition to obesity has a polygenic basis, which means that obesity will develop if an individual has several polygenic variants that increase body weight. The FTO gene was the first GWAS-identified obesity-susceptibility gene and since then other polygenic variants that are associated with BMI and dietary intake have also been identified. However, this is still an active area of research as more polygenetic variants await discovery.

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Purpose. Exercise performed improperly, in disagreement with age and development, may trigger negative bioactive effects. Adolescent taekwondo athletes, being able to practise on tatami or without tatami and barefoot, may be submitted to musculoskeletal structure disorders. the purpose of this study was to describe the frequency and amplitude of the reactive forces during taekwondo practice with and without tatami. Methods. Overall, 27 adolescent taekwondo athletes aged 10-15 years were submitted to a standard 90-minute training session with and without tatami. During each session, the frequency of ground contacts and the vertical ground reaction forces were measured. Femur and wrist bone age and the respective stages of the epiphyseal plate were computed from radiograph images. A total of 6346.6 ± 425.5 ground contacts (an average of 106 contacts per minute) were registered during the training session. the Wilcoxon test was applied to analyse the relationship between taekwondo and epiphyseal plate stage (p 0.005). Results. Student's t-test revealed a significant difference between ground reaction forces with and without tatami; tasks performed without tatami featured smaller magnitudes for comparisons of absolute and normalized values (t = -3.359; p < 0.002 and t = -3.652; p < 0.001, respectively). the time of practice showed no early closure of the femur epiphyseal plates caused by the practice of taekwondo. Conclusions. Practising taekwondo seems to have a bio-positive effect on the maturation of adolescent athletes, regardless of the use of tatami.

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