Purpose <p>The optimal postoperative nutritional management after lung transplantation (LT) remains unclear. This study evaluated the effectiveness of an early postoperative nutritional protocol on the nutrition-related outcomes.</p> Methods <p>We retrospectively analyzed 50 patients who underwent LT between 2019 and 2021 at our institution. From 2020, 22 patients were managed using a nutritional protocol aiming to initiate nutritional support by postoperative day (POD) 3 and achieve the target energy and protein intake by POD 7. Postoperative changes in body weight and muscle mass were compared between the pre- and post-protocol groups over a period of 3 months.</p> Results <p>The perioperative characteristics were comparable between the groups. The initiation of enteral and central parenteral nutrition within 3 days was more frequent in the post-protocol group than in the pre-protocol group (45% vs. 7%, <i>p</i> = 0.002; 82% vs. 29%, <i>p</i> &lt; 0.001). Energy and protein sufficiency on POD 7 was higher in the post-protocol group (84% vs. 69%, <i>p</i> = 0.011; 87% vs. 74%, <i>p</i> = 0.017). Weight loss at 2 weeks after LT was attenuated in the post-protocol group and remained suppressed. Although muscle mass declined at 2 weeks in both groups, recovery within 3 months was greater in the post-protocol group.</p> Conclusion <p>Early postoperative nutritional support after LT is associated with reduced weight loss and an improved muscle mass recovery.</p>