Introduction Overweight in adolescents is worldwide and have been growing fast in the three last decades. In Brazil, data from three national surveys show that prevalence of overweight among male fivefold from 1974–1975 to 2002–2003 and flat among female from 1989 to 2002–2003.

Objective To update changing trends of overweight among Brazilian adolescents across last 4 decades.

Methods Data are age-ranged 10–19 years and come from four nationwide surveys: ENDEF-1974–1975, PNSN-1989, POF-2002–2003 and POF 2008–2009. Overweight was classified according to IOTF's purpose as the BMI values greater than the adult equivalent 25 kg/m² critical values. Change in risk of overweight across survey periods was estimated using ratio of prevalence (RR).

Results Among boys, prevalence of overweight was 2.4, 5.7 and 13.2 and 17.3% at 1974–1975, 1989, 2002–2003 and 2008–2009, respectively; among girl, prevalence of overweight was 6.0, 11.8, 12.5 and 16.3% at same survey, respectively. From 2002–2003 to 2008–2009 overweight increased across all age groups and income strata, both sexes. RR for changing trends from 1974–1975 to 1989, 1989 to 2002–2003 and 2002–2003 to 2008–2009 among the fifth poorest male are 2.6, 7.5, 10.1, respectively and among the fifth richest male are 2.1, 3.3 and 4.4, respectively. Among the poorest female RR are: 2.1, 2.4 and 3.7 and among richest fifth are 2.0 1.5 2.1, respectively.

Conclusion In general, overweight expanded stronger in the last decade. Female adolescents in Brazil has reversed flat trend and are going to increase body mass index at all age and income strata.