Eating disorders are notoriously difficult and costly to treat, with only 40% of individuals with an eating disorder making a full recovery. Individually Tailored Service Allocation provides a dynamic treatment model defined by empirically accepted theory and consistently informed by data provided by the patient. The use of patient feedback allows for the tailoring of individual treatment plans to meet the unique and varied needs of each patient. Hierarchical Linear Modeling was used to examine the effect of Individually Tailored Service Allocation on eating disorder treatment outcomes. A total of 51 adult women meeting diagnostic criteria for an eating disorder participated in this study. Participants were randomly assigned to treatment as usual or individually tailored treatment groups. Changes in psychological dysfunction and distress were measured biweekly throughout the course of treatment using the Outcome Questionnaire 45. The results of this study indicate variability in levels of global psychological dysfunction (both within and between subjects) throughout the course of treatment appear to be the norm, rather than an exception, and this variability is related to eating disorder treatment outcomes. The choice of treatment methodology and level of Individually Tailored Service Allocation has the ability to drastically shift treatment outcomes.