Childhood obesity is a global health crisis and contributes to shortened life expectancy in the US, with higher rates and more serious co-morbidities among minorities. Existing dietary interventions demonstrate significant heterogeneity of treatment response among diverse populations, and clear information to tailor diet to individual-level characteristics is not yet available. Recent science suggests that the gut microbiome may in part explain inter-individual variation in pediatric obesity and treatment response. Intestinal microbial communities play causal roles in models of obesity and are distinct between individuals. However, it is unknown how the microbiome mediates response to existing dietary guidelines for children with obesity.

Evidence-based nutritional standards for treatment of pediatric obesity are well-established, and aim to reduce body mass index and cardio-metabolic risk. However, these standards have not translated into reduced prevalence of obesity among children, particularly those in racially diverse and low-income groups. One explanation is the significant inter-individual variability in metabolic response to dietary interventions, suggesting that certain food components in a diet may benefit some individuals more than others. Another explanation is that dietary adherence is highly variable, and requires skills or resources not available to all people. For example, translating dietary recommendations into food procurement, preparation, and consumption requires baseline levels of educational attainment, child acceptability of foods, diet compatibility with cultural preferences, and may be seen as time-consuming. These obstacles are hard to overcome for children and families from low-income and minority groups, who are known to have low show rates and engagement in nutrition studies despite being at disproportionate risk of diseases like obesity and metabolic disease. The one-size-fits-all approach to dietary recommendations is failing the most vulnerable children in the nation.

Recent science suggests that the gut microbiome provides new opportunities to address these long-standing challenges. Microbiome transplant experiments in mice have demonstrated that increased adiposity can be conferred from bacterial communities originating from individuals with obesity. Furthermore, variation in microbiome composition between individuals can predict response to dietary intervention, suggesting a mechanism for why certain individuals lose weight on specific diets and other individuals do not. Another intriguing aspect of microbiome science is how its adoption could introduce new methodological techniques to obesity treatment. In particular, the plummeting costs and turnaround times of metagenomic DNA sequencing used in microbiome research opens new opportunities for rapidly providing biomarker information to a wide number of people. \|

No evidence exists that describes microbiome signatures with objective measures of dietary quality among children with obesity. The work to be completed here will be a vital first step towards integrating the promise of microbiome science into the treatment of pediatric obesity. Our team is uniquely suited to take this step as leaders in microbiome science (David) and childhood obesity (Armstrong). By working together to predict how individual microbiome variation shapes responses to diet therapy, an important step towards personalizing dietary recommendations for children based on gut microbiome signatures that predict the best outcome will be taken. In addition, linking microbial signatures to measures of diet quality will provide researchers with much-needed molecular tools for assessing dietary compliance and intervention success. Finally, insights into the impact of receiving metagenomic data on children's' motivation towards healthy behaviors could provide behavioral and implementation scientists with new tools for improving adherence with obesity treatment