Restrictive lung disease is defined as a reduction in lung volume that may be due to intraparenchymal or extraparenchymal causes. Intraparenchymal causes falls under the umbrella term of interstitial lung disease (ILD) and includes idiopathic pulmonary fibrosis. This manuscript provides an overview of ILD and can be beneficial for all clinicians working with patients with ILD. Although not well documented, the prevalence of malnutrition in patients with ILD has been reported to be between ~9% and 55%. Body mass index has been shown to predict survival; but more recently, research has suggested that fat‐free mass has a larger influence on survival. There is insufficient evidence to support the use of antioxidant or vitamin supplementation to help diminish the chronic inflammatory process that is seen in this patient population. There are data from studies examining the vitamin D status in this patient population, but research on vitamin D supplementation appears to be lacking. Registered dietitian nutritionists should continue to advocate and play a more prominent role in the nutrition management of patients with ILD as part of standard of care.