Dietary manipulation may influence outcome after infection and injury by altering production of inflammatory mediators and disease activity. Restricted nutrient intake may have beneficial effects on life-span, development of degenerative disease, autoimmune processes, renal injury, susceptibility to infection, and survival rate after infection. Nutritional therapies that serve to maximize nitrogen balance may adversely affect the host response to injury, especially when given in excess of energy and protein needs. The optimal calorie/protein intake during different phases of critical illness remains to be established. However, a short period of restricted intake may be beneficial.