Influência da percepção do peso e do índice de massa corporal nos comportamentos alimentares anormais Influence of body mass index and body weight perception on eating disorders symptoms

OBJETIVO: Estudar a associação entre a percepção do peso corporal, o índice de massa corporal e os comportamentos alimentares anormais. MÉTODOS: Delineamento transversal, de base populacional, com mulheres de 12 a 29 anos, da zona urbana de Porto Alegre, RS (n=513). Para medir a prevalência de comportamentos alimentares anormais utilizou-se o Teste de Atitudes Alimentares 26 (EAT-26) e o Teste de Investigação Bulímica de Edimburgo (BITE), considerados separadamente e em conjunto, e a percepção do peso corporal por meio de 2 perguntas estruturadas: qual era o peso que a mulher julgava ideal e a auto-avaliação sobre seu peso. O índice de massa corporal (IMC) foi calculado por medida de peso e altura aferidos. RESULTADOS: Considerando os instrumentos conjuntamente, 30,2% das mulheres tinham comportamento alimentar de risco, e 11,3% apresentaram comportamento alimentar anormal. Além disso, 82% das mulheres apresentaram IMC normal, sendo que 2% eram magras, e 16% apresentaram IMC de sobrepeso/obesidade. Das mulheres estudadas, 46% tinham o ideal de pesar menos, e 37,8% consideravam-se gordas. Entre as mulheres com IMC normal, 25,2% das que se achavam normais apresentavam comportamento alimentar de risco, e 5,7 % comportamento alimentar anormal. Das mulheres que se consideravam gordas, 47,2% apresentaram comportamento alimentar de risco, e 19,2% tinham comportamento alimentar anormal. Mulheres que se sentiam gordas apresentaram um risco quatro vezes maior de apresentar comportamentos alimentares anormais (razão de odds 4,50; IC 95% 2,88-7,01; pOBJECTVE: To investigate the relationship between body mass index (BMI), body weight perception and eating disorder symptoms. METHODS: A population-based cross-sectional study was conducted among women aged between 12 and 29 years old in Porto Alegre, Brazil (n=513). The prevalence of eating disorder symptoms was assessed by using two instruments: the Eating Attitudes Test - 26 (EAT-26) and the Bulimic Investigator Test (BITE). The results of the screening tests were evaluated separately and as a score combination of both instruments. Body weight perception was assessed using two questions: a) what was regarded as the ideal weight, and b) self-perception of body weight. The body mass index was calculated by dividing the square of the height (cm) by the weight (kg). RESULTS: Regarding the results of the combined scores, 30.2% of the interviewed women were classified as having risk of eating disorder and 11.3% had abnormal eating behavior. The sample's mean BMI was 21.9 (SD=3.8); 82.4% were classified as normal, 1.6% as thin and 16.1% as overweight/obese. Of the total of the study women, 46% had an ideal weight lower than their actual weight and 37.8% considered themselves fat. Among women with normal BMI, 25.2% that were classified as normal presented risk of abnormal eating behavior and 5.7% had eating disorder symptoms. Among women who considered themselves fat, 47.2% presented risk behaviors and 19.2% had eating disorder symptoms. The risk for eating disorder symptoms among women who saw themselves as fat was four times higher than among those who perceived their weight as normal (odds ratio 4.50; 95% CI 2.88-7.01; p