BACKGROUND: We conducted a prospective study to advance knowledge of biological factors that predict the future onset of binge eating and compensatory weight control behaviors because few biological risk factors for eating pathology have been identified. METHODS: Adolescent girls free of binge eating or compensatory behaviors ( RESULTS: Elevated responsivity of regions implicated in attention and valuation (dorsal anterior cingulate cortex
ventromedial prefrontal cortex) to thin models and lower responsivity of a reward valuation region (caudate) to anticipated milkshake tastes (which correlated with feeling fat) predicted the future onset of binge eating or compensatory behaviors over 4-year follow-up. Parental history of binge eating and compensatory behaviors, emotionality, weight/shape overvaluation, feeling fat, and elevated BMI also predicted the future onset of binge eating or compensatory behaviors. CONCLUSIONS: The evidence that elevated attentional bias for, and valuation of the thin ideal, in combination with lower valuation of high-calorie foods, predicted the future onset of eating-disordered behaviors are novel findings. The evidence that weight/shape overvaluation, feeling fat, elevated body mass, emotionality, and parental history of eating pathology predicted the future onset of eating-disordered behaviors extend past findings.