The purpose of this research was to examine psychosocial and body weight correlates of dietary behavior in low-income tri-ethnic women. In Study 1, a semi-quantitative food frequency questionnaire (FFQ) was developed and validated against diet records in 95 college women and 50 low-income postpartum women. Pearson's correlations were 0.42 among college women and 0.45 among low-income women. Cross-classification of participants into quartiles resulted in 76% of college women and 79% of low-income women being classified correctly. These results suggested that the FFQ was valid for dietary assessment among young women in the southwestern United States. In Study 2, approximately 160 mothers were recruited in the hospital 0-1 days following childbirth, and prepregnancy weight and demographic information were obtained. Weight was measured at 6 months and 1 year postpartum; psychosocial factors were assessed at 1 year. Diet during pregnancy and postpartum was assessed via food frequency questionnaires administered at 1.5 months, and at 6 and 12 months postpartum, respectively. From pregnancy to postpartum, % calories from fat (delta = +1.1%, p<0.05) and added sugar (delta = +2.0%, p<0.05) increased. A greater percentage of lactating than non-lactating women (64% vs. 38%, p<0.05) met recommendations for fruits during pregnancy. Mean intakes of calcium, vitamin A and dairy foods were higher in women who had retained <10% of their prepregnancy weight at 1 year postpartum than in those who had gained [greater-than or equal to] 10%. During late postpartum, women in the highest tertile of compliance with dietary recommendations had a more positive body image (p<0.041) than those in the lowest tertile, and less neglect of self-care (p<0.001), weight-related distress (p<0.006), stress (p<0.009), depressive symptoms (p<0.020), and perceived barriers to weight loss (p<0.039). These findings suggest that the transition from pregnancy to postpartum is associated with a negative impact on dietary behavior in low-income women. Intakes of calcium, vitamin A and dairy foods may be associated with lower weight retention in postpartum. Furthermore, psychosocial variables may influence adherence to dietary guidelines during this time. / text