Anorexia nervosa (AN) is associated with thermoregulatory disturbances such as hypothermia. However, few studies have explored body warmth in AN patients. In this study, we assessed the body surface temperature distribution in adolescent AN patients using high-resolution infrared thermal imaging and through a patient questionnaire, and explored how this differed between intervention and control group and length of treatment. Adolescent AN patients admitted to a multimodal inpatient treatment programme based on an integrative perspective were assessed at three time-points: admission (t1), 6 weeks post-admission (t2), and 3 months after t2 (t3). Healthy control participants were assessed once at baseline. In both groups we assessed participants’ surface temperature and the perception of warmth, using thermal imaging and a questionnaire, in the face, hands, abdomen, and feet. We recruited 40 AN patients and 40 healthy controls, who were admitted to the treatment programme for an average of 70 days (SD = 24.07). The AN patients were significantly colder in all chosen body domains, except the abdomen area, at t1 compared to healthy controls at baseline. The questionnaire findings supported this result. Differences between the intervention and control groups noted at t1 were significantly reduced by t2 and t3. Our findings suggest that abnormities in the body warmth distribution of AN patients are reversible after having received an AN-specific treatment. Reducing the loss of warmth could improve therapeutic outcomes in AN patients and be a predictor of recovery, and should be investigated in further studies.