Adiposity is a chronic disease that must be treated from childhood. Despite the transcendence of improving habits, few interventions report their contribution to decreasing adiposity. Methods: This cohort enrolled children and teens of any gender, 8–18 years old, and with a body mass index (BMI) z-score of ≥1 into “Sacbe”, a comprehensive program to identify which eating habits could reduce BMI z-score. The sample size calculated was 110 participants. We recorded anthropometric measures, clinical history, and habits. A clinically relevant reduction in BMI z-score was defined as ≥0.5 over 12 months or its equivalent according to the months of follow-up. Results: 58.2% were female, the median age was 12 years (range: 9.1–14.7), and the mean BMI z-score was 2.30 ± 0.83. The 82.7% achieved a reduced BMI z-score but 41.8% achieved a clinically relevant reduction with a median follow-up of 6.7 months. Eating out less than once per week was associated with this outcome, even after adjusting for energy intake, other eating patterns, sedentary screen time, physical activity, sleep duration, and sitting time (HR 2.12; 95% CI: 1.07–4.21). Conclusions: Eating out < once/week implicates less processed food exposition and better quality of food; this habit could be the most effective to reduce childhood adiposity.

Background/Objectives: Bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) are the gold standard to measure fat mass, but they are unavailable in regular consultations. Relative Fat Mass (RFM) and Pediatric Relative Fat Mass (pRFM) equations are calculated using DXA images in adults and children, but they have not been correlated with BIA. Methods: A longitudinal prospective study was conducted with 531 children from a public school followed over one year; sex, age, weight, height, waist circumference and fat mass percentage were recorded. We calculated body mass index Z-score (Z-BMI), body mass index percentile (Pc BMI), waist-to-height ratio (WHtR), and RFM-pRFM to diagnose Overweight (Ow)/Obesity (Ob). We used descriptive statistics, Pearson’s correlation, sensitivity and specificity, 95% CI, and ROC curves; SPSS version 22 was used. Results: Adiposity was found in 34.5%, 33.2%, 21.5% and 43.5% of children using Z-BMI, Pc BMI, WHtR, and BIA, respectively; excluding children younger than 8 years old, the frequency of adiposity was 51.5% by RFM-pRFM. The highest correlation was between RFM-pRFM and BIA (0.84, p < 0.000). Of the total measurements of each visit considered as normal weight using Z-BMI, 21.5% had adiposity using BIA, and the proportion of girls underdiagnosed was twice that of boys. Conclusions: RFM-pRFM had the highest correlation with BIA but Z-BMI, Pc BMI, and WHtR are also helpful. It is important to consider that 21.5% of children with apparent normal weight present adiposity.

Rs9939609 marker in FTO Alpha-Ketoglutarate-Dependent Dioxygenase (FTO) gene, rs7895307 in Transcription Factor 7-Like 2 (TCF7L2) gene, and rs75493593 in Solute Carrier Family 16 Member 11 (SLC16A11) gene have been associated with anthropometric, metabolic, and clinical variables, but have not been concurrently studied in Mexican children and adolescents with adiposity or mental disorders. In this cross-sectional association study, we genotyped these markers by means of TaqMan real-time polymerase chain reaction in two at-risk pediatric cohorts recruited in Mexico City. Group 1 (n = 175) comprised children and adolescents with overweight/obesity. Group 2 (n = 296) consisted of non-medicated adolescents meeting the Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria for Attention Deficit/Hyperactivity Disorder or a mood disorder. Anthropometric measurements (body mass index —BMI—, waist circumference, body fat percentage), metabolic indices (fasting glucose, lipid profile, Homeostatic Model Assessment for Insulin Resistance), and psychiatric diagnoses were evaluated. In Group 1, the FTO A allele (genotypes AA/AT) was significantly associated with severe obesity according to BMI Z scores (p = 0.004, O.R. 3.33, 95% CI [1.42–7.77]), and it was a predictor of waist circumference (B = 6.16, 95% CI [1.78–10.55], p = 0.006) and muscle percentage (B = 4.21%, 95% CI [0.91–7.51%], p = 0.013) using linear regression models adjusted for age and sex. In Group 2, TCF7L2 AA genotype was associated with increased odds of depression (B = 0.83, p = 0.003, OR = 2.29, 95% CI [1.32–3.96]). While SLC16A11 G allele showed a possible association with insulin resistance or glucose levels, confirmation is needed. These exploratory results highlight the need for larger, well characterized cohort studies to confirm the associations.