This case describes a woman in her 20s with a 6-month history of progressive exertional dyspnoea and cough. Examination revealed hypoxia on room air, sinus tachycardia, finger clubbing and bibasal inspiratory crackles. Inflammatory markers were mildly elevated and empirical antimicrobial therapy was commenced. A multidisciplinary discussion consensus diagnosis of acute interstitial pneumonitis was made based on the findings of high-resolution CT of the chest, macrophage predominant bronchoalveolar lavage cell differential and surgical lung biopsy. There was clinical and radiological deterioration despite glucocorticoids and antifibrotic therapy. A body mass index of 37.5 kg/m2 precluded her from lung transplant assessment and consideration. Following consultation with the weight management service, she was commenced on glucagon-like peptide 1 (GLP-1) analogue therapy. She had a remarkable response within 6 months, was listed for lung transplantation, and within 18 months of her initial presentation, a double lung transplantation was performed.