Chronic psychological distress appears to be increasing markedly among the working population. A recent randomized controlled trial (RCT) supported the effectiveness of a three-week outpatient burnout prevention program—comprised of stress management interventions, relaxation, physical exercise, and moor baths followed by massage—in reducing perceived stress and emotional exhaustion. However, the effectiveness of treatments in the real world that were shown to be efficacious in RCTs is related to the appropriate selection of individuals who are most likely to yield sustainable gains. Therefore, factors predicting the intensity of response and nonresponse of individuals to treatment are of interest. This secondary data analysis aims to explore predictors of response to the outpatient burnout prevention program in a sample of eighty employed persons at high risk of burnout. Hierarchical linear regression was performed to identify predictors of successful response—defined by lower perceived stress at last follow up. Nutritional behavior, symptoms of eating disorder syndrome, and well-being were significant predictors of perceived stress at last follow up, when adjusted for age, sex, education level, baseline stress values, and timing of intervention. Persons with low levels of well-being, poor nutritional behavior, and higher symptoms of eating disorders should be given special care and attention to ensure that they respond well to the outpatient burnout prevention program.