Abstract Background Thermal injury is associated with significant weight loss, particularly of lean body mass. Weight loss increases the risk of morbidity and increased length of stay (LOS). Appropriate nutrition support can improve these outcomes. The aim of this audit was to evaluate the success of nutrition intervention in minimizing weight loss in adults and children with thermal injury. Method Patients referred for nutrition support were monitored for weight change during their inpatient care episode. Sixty cases met the study criteria. Admission and discharge weight profiles were identified. The degree of weight loss was calculated. Comparison was made to a recognized standard of acceptable weight loss. Results On admission five (13.2%) adults were found to be clinically underweight. All children were within the acceptable weight percentile range. Adults demonstrated higher (mean ± SD) percentage weight loss (8.1 ± 6.0%) than children (4.7 ± 4.5%). About 76.7% of all cases met the standard used. More children (95.5%) met the standard than adults (65.8%). Conclusions Most subjects maintained weight within an acceptable limit during the inpatient episode. Children appeared particularly successful at weight maintenance. Reasons are multifactorial and warrant further investigation.