Introduction: eating disorders (ED) such as anorexia nervosa (AN) or bulimia nervosa (BN), as well as obesity (OB), are related to emotional and neuropsychological impairments on measures of cognitive flexibility, central coherence or decision making. However, little is known about the association among emotional regulation, neuropsychological variables and affect. Objectives: to analyze whether neuropsychological and affect variables can predict emotional regulation in ED and in OB. Methods: thirty females with restricting ED (restricting AN) were assessed, 18 with purging ED (purging AN and BN), 33 with OB and 39 healthy controls matched for intelligence. The Wisconsin Card Sorting Test (WCST) assessed cognitive flexibility, the Group Embedded Figures Test (GEFT) assessed central coherence, the Iowa Gambling Task (IGT) assessed decision making, the Positive and Negative Affect Schedule assessed positive (PANAS-PA) and negative (PANAS-NA) affect, and the Difficulties in Emotion Regulation Scale (DERS) assessed emotional regulation. Results: relative to the healthy control group, ED and OB groups performed worse on IGT (p = 0.002) and GEFT (p = 0.003), had lower scores on PANAS-PA (p = 0.001) and higher scores on DERS (p < 0.001). ED groups had higher scores on PANAS-NA tan both OB and healthy controls (p = 0.001). PANAS-PA, PANAS-NA and IGT accounted for 51.4% of the variance of the DERS (p < 0.001). Conclusions: our study shows a significant association between decision making, affect and emotional regulation in the continuum from AN to OB, and also highlights the importance of including programs focused on decision making and affect in cognitive interventions for ED and OB.