The main objective of this randomized controlled trial (RCT) is to investigate whether a multimodal prehabilitation intervention combining a mixed-nutrient supplement with structured exercise training (MM) or the supplement alone (NUT), against a placebo (CTRL), leads to improvement in functional capacity and postoperative outcomes in surgical patients with lung cancer, at nutritional risk. This will be tested in a single centre RCT of 3 parallel arms, double-blinded for the supplement. Female and male participants (n=168, \>=45 y) will be randomized to a 10-week intervention spanning 4 weeks pre-surgery and 6 weeks post-hospital discharge. The primary outcome is functional capacity as measured by the 6-minute walk test. Secondary outcomes include muscle mass, quality and strength, quality of life, length of hospital stay, and postoperative complications.