The aims of the present research were to explore the practical management of cancer cachexia, a severe wasting syndrome commonly associated with advanced cancer. The research was conducted in three distinct phases. The purpose of the first phase was to systematically review, critically appraise and synthesise, randomised clinical trial data to evaluate the effectiveness of the omega-3 fatty acid, eicosapentaenoic acid (EPA) to alleviate the symptoms of cancer cachexia. The findings from five included trials revealed that there was insufficient evidence to recommend its use within clinical practice. The second phase consisted of a pragmatic, randomised controlled trial to investigate the efficacy of an oral nutritional supplement containing 2g of EPA to stabilise weight loss, promote weight gain, appetite, performance status and survival. Twenty-seven patients with mixed cancer tumour types were randomised to daily consume a nutritional supplement either with or without EPA for 8 weeks. The key findings from this study were that there were no statistically significant improvements in gross weight gain, lean body composition, appetite, physical performance or quality of life. However, the study was underpowered and sample size not achieved. Finally, the third phase of this study used a qualitative approach to provide a descriptive, interpretative study to explore nurses' management of patients with advanced cancer and weight loss. Fourteen nurses from both primary and secondary care settings took part in one-to-one audio taped interviews. The findings revealed that many nurses adopted an ad-hoc, reactive style of nutritional management, which did not routinely provide for early identification and assessment of weight loss, or monitoring of the patient's nutritional status. However, the majority of nurses interviewed received little or no training in nutritional management and based their decision-making on both personal experience and anecdotal accounts.