In this study, we will test the following hypothesis: A high-leucine essential amino acid mixture stimulates whole body protein synthesis (and in this way protein anabolism) to a larger extent than a regular balanced mixture of total (essential and non-essential) amino acids in NSCLC patients with and without recent weight loss. The principal endpoint will be the extent of stimulation of protein synthesis rate as this is the principal mechanism by which either amino acid or protein intake causes muscle anabolism. This project will provide important clinical information, based on novel fundamental basic knowledge on the process and the specific underlying mechanisms of muscle wasting in patients with NSCLC, and the role of EAA as a potential anabolic substrate. In this way, it will provide preliminary data for the development of nutritional strategies that will prevent or even stop this process of ongoing muscle loss in NSCLC.