The 2015 ESPEN Arvid Wretlind lecture. Evolving concepts on perioperative metabolism and support.

The aim of the present lecture is to review the changes in perioperative nutritional policy throughout years. Many advances on both knowledge and clinical practice occurred with time, particularly on preoperative patient assessment and preparation, modulation of surgical stress, identification of the gut as regulator of postoperative inflammatory response, and perioperative fasting policy. Improvement of patient's condition should be obtained by recognizing and treating undernutrition, optimizing body composition, and encouraging physical activity perioperatively. The use of specific nutrients with metabolic effects as well as reducing both preoperative and postoperative fasting within an enhanced recovery pathway can help to modulate postsurgical stress.