Although much has been learned about the nature of childhood obesity, the problem remains exceedingly difficult to prevent and treat.
By and large, although intensive family-based interventions can be efficacious over the short term, the effect of individual-level approaches alone, including education and skill-based techniques, are difficult to sustain .
The focus of research on childhood obesity has shifted during the past three decades.
Research began with mostly medical studies documenting the natural history and physiological sequelae of obesity, followed by individual- and family-based interventions, and, more recently, environmental correlates of and policy approaches to childhood obesity.
Among adult-sibling models, the contribution of time-constant factors remained relatively high (33–38 %), but time-changing factors explained less variation (5–15 %).  showed that a common environment explained 74–87 % of variation in body height, weight, and body mass index (BMI) among twins at early ages, but the variance explained was markedly reduced to less than 20 % by age 19 years.
These studies point to the importance of targeting family and social environments in early childhood.In recognition of the need for greater and more sustained population-level impact, recent efforts began to identify attributes of the built environment in relation to diet and physical activity as well as to debate the merit of policy interventions, such as menu labeling mandates or soda taxation, to incentivize healthy behaviors and disincentivize unhealthy ones .The purpose of this review is to provide a critical analysis of the state of the science in population-based childhood obesity research.Evidence on the influence of home and built environments has strengthened with recent research.Three studies on exposure to green space found positive correlations with moderate to vigorous physical activity (MVPA) [20 minutes of daily exposure to greener spaces engaged in nearly five times the daily rate of MVPA than those with nearly zero daily exposure.Of note, validation of accelerometry was performed in preschool ages, whereas prior research had mostly been in older children and adults.  identified acceptable sensitivity and specificity levels of the Activ PAL (86.7 % to 97.3 %) to predict toddler postures (e.g., sit, stand, crawl) compared with video-recorded movements.In the pursuit of simpler measurement tools, pedometers were compared with accelerometry in several studies of school-age children to determine step-count cut-points that correlated with levels of activity intensity [••] furthered the methodology to combine accelerometry and global positioning system (GPS) by testing several data collection methods that revealed patterns of activity mapped with location information across time. [••] validated the use of ecological momentary assessment (EMA)—mobile phone surveys for capturing real-time physical activity and context—with accelerometry and found a 4-day protocol with three to seven surveys per day yielded valid physical activity levels.Development or validation of tools to measure dietary and physical activity behaviors, along with psychosocial instruments, dominated this domain.Several publications focused on the development of electronic systems for self-reported dietary intake.Studies on correlates of obesity represented almost half of the publications abstracted.A quarter of the publications fell under the prevention intervention domain.