The aim of this article is to emphasize the importance of taking into account the mechanism of host's response to insult when choosing a nutritional strategy in the early phase of a critical illness. At the same time, the article discusses the risks associated with early aggressive nutritional intervention for both energy and protein intake. Today, it seems that the most optimal choice of nutritional support during the first week of stay in the ICU is a gradual increase in both energy and protein intake. In numerical terms, this means a daily increase in energy dose of approximately 5 kcal/kg/day and a daily increase in protein dose of 0.2 g /kg/day. However, this only applies to patients admitted to the ICU with a normal body mass index, i.e. without malnutrition or without obesity. Both of these categories require special attention beyond the scope of this article.
Keywords: Hibernation; autophagy; critically ill; nutritional support; overfeeding.