Obesity is a multifactorial, complex, chronic disease of special concern. It is originated as an interaction between genetic predisposition and environmental factors. Thus, knowledge of gene-diet interactions is especially important. However, most studies analyzing the efficacy of diet on body weight have not considered the genetic variability among the population.

Childhood and adolescence are critical periods in the development of obesity. This is because, on one hand, during infancy dietary patterns are being implemented. Moreover, it has been described that around the age of 6 it occurs the adiposity rebound, which consists in the increase in body mass index (BMI) that occurs after reaching a lowest point in infancy. It is believed that an early adiposity rebound is associated with a higher risk of developing obesity in the following years. The prevalence of overweight and obese children is increasing every year. Specifically, according to the World Health Organization (WHO) the number of overweight or obese children aged 0 to 5 years, increased from 32 million globally in 1990 to 41 million in 2016. Regarding Spanish children, they are amongst the highest levels of overweight and obesity in Europe. Precisely, in 2015 the Spanish Agency for Consumer Affairs, Food Safety and Nutrition reported 23.2 % overweight and 18.1 % obese Spanish children, according to the ALADINO study.

Considering the previous elaboration, we hypothesized that an early identification of SNPs associated with obesity will improve the strategies applied for its prevention. Moreover, an adequate nutritional counseling and a healthy lifestyle implementation during childhood will contribute to a higher quality of life in the adulthood.

Thus, schools from the Madrid Community agreeing to participate in the study will be randomly assigned to either control or intervention groups. Then, an initial evaluation where 26 SNPs associated with obesity and its related comorbidities will be carried out in all children involved in the study, in addition to anthropometric, blood pressure measurements, and physical activity and dietary patterns evaluation. Then, each group will be divided in two according to the genetic risk (high vs low) for presenting obesity and its related comorbidities. The initial evaluation was performed on all children at 1st and 2nd grades and it is going to be followed by 3 monitoring actions in the following years where the progression of anthropometric measurements and dietary habits are going to be studied. Besides, the intervention schools are going to receive healthy actions along the study aimed to reduce the risk of developing obesity.

Inclusion Criteria:

Children at 1st and 2nd grades from schools of the Madrid Community that have accepted to participate in the study, whose parents have approved and signed the informed consent.