Motivational Intervention on the Gut Microbiota of Obese Children

The study will provide light to several hypothesis: ‐ The main hypothesis is that the dietetic intervention in obese children may improve the components of the metabolic syndrome by mediation (at least in part) of changes in the microbiota. Other secondary hypothesis to be demonstrated are: ‐ The microbiota (before the treatment) could be a determinant factor of the metabolic syndrome (inflamation, serum lipid profile, insulin resistance) being a key feature differentiating the metabolically healthy obese from the obese with metabolic syndrome. ‐ A dietary pattern rich in vegetables and fruits is associated to a gut microbiota profile preventing the metabolic syndrome How these hypothesis will be demonstrated? A motivational structured intervention to reduce weight is applied (under randomized clustered design) to obese children, that are compared to an active intervention (not structured) provided by health care professionals, both groups during 12 months (+3). A baseline and final assessment (before and after the intervention) are performed, in which the following information is collected: ‐ Socioeconomics ‐ Anthropometry (weight, height, waist circumference) to calculate the obesity degree (BMI z‐ score) and the presence of abdominal obesity ‐ Body composition: deuterium dilution (in a subsample), bioimpedance, Dual X‐Ray Absorptiometry and Air displacement pletismography (BodPod) ‐ Blood sample drawn: to analyze lipids profile and insulin resistance ‐ Fecal sample: the gut microbiota diversity and the presence of specific bacteria will be analyzed ‐ Dietary intake by a food frequency questionnaire: diet will be analyzed as dietary patterns ‐ Systolic and diastolic blood pressure (which will be adjusted as z‐score)