Anthropometry and other physical examinations Field measurements were performed by a nurse and a nutritionist. Height and weight were measured with children barefoot and lightly clothed using a stadiometer and a beam-scale Seca ®, with an accuracy of 50 g. The individual height and weight values were established by averaging three measurements of each parameter. BMI was calculated and expressed in percentiles and z-scores (13): z-scores were calculated according to Center for Disease Control-National Center of Statistics 2000. Nutritional status was classified according to BMI percentiles in the obese category as ≥ 95 (14). WC was measured with an inextensible tape on the upper lateral border of the right ilium in the mid-axillary line at the end of an exhalation (15) ; two measurements were averaged and the ≥ 90th percentile was used as cutoff value (16). The triceps and subscapular skin folds were measured with a Harpenden ® caliper using a standard technique (15); both were used to calculate the percentage of FM using Slaughter equations (17) previously validated in Chilean children (18, 19). Elevated FM was established as ≥ 42% for girls with 10-15 years old, ≥ 38% for boys with ≤ 12 years old, and 40% for boys with ≥ 13 years old (20).