**1. Introduction**

Childhood and adolescent obesity is a globally recognized public-health concern [1]. In addition to physical comorbidities, such as the increased risk of developing metabolic syndrome, type 2 diabetes, cardiovascular diseases, orthopedic complications, or increased rates of cancer, among others, a growing body of research has documented the psychosocial burden in affected children and adolescents [2]. Psychosocial impairments, such as a poor self-esteem, a negative self-perception or self-concept, can result in a vicious circle of weight gain [3–6]. Besides this, a negative self-concept has been found to mediate the inverse relationship between high body mass index (BMI) and health-related quality of life (HRQOL) [7], a multidimensional construct aggregating individuals' physical and psychological health, emotional state, and social functioning [8]. Already in 2014, Buttitta

**Citation:** Eisenburger, N.; Friesen, D.; Haas, F.; Klaudius, M.; Schmidt, L.; Vandeven, S.; Joisten, C. Predicting Psychosocial Health of Children and Adolescents with Obesity in Germany: The Underappreciated Role of Physical Fitness. *Int. J. Environ. Res. Public Health* **2021**, *18*, 11188. https://doi.org/10.3390/ ijerph182111188

Academic Editors: Clemens Drenowatz and Klaus Greier

Received: 16 September 2021 Accepted: 22 October 2021 Published: 25 October 2021

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et al. concluded in a review of HRQOL in children and adolescents with obesity, that scientific findings regarding the obesity-related impairment in all dimensions of HRQOL of children and youth were mostly congruent [9].

Consequently, in addition to weight reduction/stagnation and lifestyle counseling, improving mental health, including HRQOL and self-concept, plays a central role in weight management programs [4,10]. To target therapeutic strategies accordingly, the identification of potential inhibitory and promotive obesity-relevant factors for psychosocial health has become a research priority [8–11]. In this regard, evidence suggests that sex, age, socioeconomic status, and migration background not only affect the prevalence of obesity in children and adolescents but also their HRQOL and self-concept [8,12–14]. Further key determinants of both weight status and psychosocial health are lifestyle patterns, such as level of physical inactivity or sedentary behavior, which is characterized by energy expenditure ≤1.5 metabolic equivalents and predominantly involves prolonged sitting and/or laying (e.g., screen-viewing activities, passive transportation) [15,16]. An objective measure of physical activity levels and sedentary behavior is physical fitness [15]. Thus, prior research indicates that it is important to also include physical fitness in the analysis of psychosocial health [17]. Studies with non-overweight children have yielded promising results in terms of psychosocial improvements associated with increased fitness [18–20]. Knowing that physical fitness is a mediator in the relationship between childhood and adolescent obesity and self-concept [21,22] and HRQOL [15,23,24], supports the need to further investigate its predictive potential for the psychosocial health of affected children and adolescents. Therefore, the aim of this cross-sectional analysis was to examine determinants of weight-specific HRQOL and subdomains of self-concept in the context of obesity in childhood and adolescence, while considering physical fitness as an additional potentially relevant predictor. Given the vicious cycle between mental health and weight gain, identifying the factors underlying this dynamic may contribute to the development of more effective weight management strategies and recommendations for improved care.
