Cancer cachexia, characterized by involuntary weight loss and extensive muscle and adipose tissue wasting, is a major contributor to morbidity and mortality in cancer patients. To date, no effective medical intervention can completely reverse this multifactorial syndrome, which is driven by different metabolic changes. Identification of cachectic patients is primarily based on alterations in body composition and the assessment of systemic metabolic and inflammatory changes. While these changes have been thoroughly described in patients with more advanced stages of lung cancer, their role in resectable lung cancer remains less explored. In this review, we summarize the different methods to assess body composition metrics such as skeletal muscle (SM) mass, fat distribution and overall body composition. As the dominant driver of cancer cachexia, we also describe the two most widely accepted acute phase proteins. Furthermore, we discuss the short and long-term clinical implications of cancer cachexia and the corresponding body composition and inflammatory changes in resectable lung cancer patients. Finally, we explore the possibility of identifying a specific host phenotype of cachectic lung cancer patients that predisposes to adverse outcomes of lung cancer surgery, which might enhance the predictive value for overall survival and aid in treatment decision-making in lung cancer patients in the future.