Underfeeding and overfeeding during critical illness Overfeeding has important adverse effects during critical illness
(Chwals 1994; Zaloga 1994). Excess carbohydrate intake can increase carbon dioxide production and impede ventilator weaning (Chwals 1994). Excess protein does not prevent catabolism and can even increase catabolism of body protein (Chwals 1994; Shew 1999; Stroud 2007). High calorific intake can increase fat deposition, including in the liver (Chwals 1994; Hart 2002; Zaloga 1994). In animalmodels, lower calorific goals were associated with weight loss and improved survival from critical illness (Alexander 1989; Yamazaki 1986). Some adult human studies suggest that underfeeding during critical illness is associated with improved survival and reduced length of stay in hospital (Ash 2005; Boitano
2006; Dickerson 2002; Jeejeebhoy 2004; Krishnan 2003). This is
compatible with the finding in many types of animals that a 30%
to 50%restriction of calories increases their lifespan and resistance
to diseases of aging and oxidative damage (with similar pathophysiology
to critical illness inflammatory cascades) (Bordone 2005).