Navigating the national rollout: examining Primary Care Network link workers and the integration of local social prescribing models in Redbridge.

Childhood obesity is a global public health concern characterized by excessive accumulation of body fat that negatively affects the health and well-being of children. The World Health Organization (WHO) reports that the global prevalence of childhood obesity has increased dramatically, with over 390 million children and adolescents (aged 5–19 years) and an estimated 37 million children under the age of 5 classified as overweight or obese. Childhood obesity is strongly associated with an increased risk of developing chronic disease in adulthood, such as cardiometabolic disorders, musculoskeletal complications, and cancers []. In addition to physical health complications, childhood obesity is also associated with significant social and psychological challenges, including poor self-esteem, feelings of loneliness, an elevated risk of depression, and social stigmatization [, ]. These factors can seriously impact a child’s quality of life and psychosocial development. However, many of these associated physical and psychological challenges can be effectively mitigated by adopting and maintaining an active and health-conscious lifestyle. Traditional physical activity interventions targeting pediatric obesity typically emphasize aerobic exercise, strength training, and recreational sports, with the primary aim of improving energy balance and reducing excess adiposity. However, these approaches often pay more attention to managing body mass index (BMI) through caloric restriction and increased physical activity, which may result in the loss of both fat and muscle mass. This loss of muscle, in particular, can negatively impact metabolic health and physical function [, ]. Skeletal muscle plays a critical role in metabolic homeostasis, serving as a primary site for glucose uptake and amino acid storage [, ]. Loss of muscle mass can reduce the availability of protein and energy substrates, which negatively affects recovery from illness, slows wound healing, and reduces basal metabolic rate []. In addition, skeletal muscle contributes approximately 20%–30% of total resting energy expenditure (REE), indicating its important role in maintaining energy balance []. Reduction in muscle mass may therefore lower REE, impair metabolic function, and increase the likelihood of fat accumulation and weight regain over time [, , ]. These limitations suggest that evaluating intervention effectiveness through BMI alone may overlook meaningful improvements in body composition and metabolic health. Muscle-to-fat ratio (MFR), defined as the proportion of skeletal muscle mass relative to fat mass, has recently been considered as a critical indicator of metabolic health [–]. Unlike BMI, which reflects total body mass relative to height but does not distinguish between lean and adipose tissue, MFR is capable of balancing the relationship between metabolically protective and metabolically detrimental compartments. Skeletal muscle serves as a primary site for glucose disposal and insulin-mediated metabolic regulation, whereas excess adipose tissue is associated with systemic inflammation and cardiometabolic dysfunction [, , ]. Therefore, the relative proportions of these tissues may provide a more physiologically informative representation of metabolic status than total body weight alone. Emerging evidence suggests that lower MFR is associated with increased cardiometabolic risk, reduced physical function, and higher likelihood of metabolic syndrome in both pediatric and adult populations [, ]. Importantly, during growth and maturation in childhood, improvements in body composition may not always be reflected by reductions in BMI. Exercise interventions that reduce fat mass while preserving or enhancing muscle mass may bring significant metabolic benefits even in the absence of substantial BMI change. Given this relationship, interventions aimed at reducing fat mass must also prioritize the preservation of muscle mass, particularly in the pediatric population, to maintain metabolic health and prevent long-term complications.