ABSTRACT
Lack of adequate caloric intake shifts the body’s neurohumoral mediators so that the balance between anabolism and catabolism is tipped in favor of catabolism. Two types of starvation have been recognized. Simple starvation is a lack of adequate calories and protein, whereas stress starvation is a consequence of systemic inflammation and physiologic stress (critical illness and injury) concurrent with a lack of adequate calories and protein. In animals without injury or illness, several metabolic adaptations result from the lack of nutrient intake. The physiologic stress associated with severe illness or injury often leads to a pronounced catabolic state characterized by hypermetabolism that is compounded by patients that are unable or unwilling to eat. The effects of starvation are well documented, both clinically and experimentally. Despite the known consequences of calorie and protein restriction, there is much debate over whether providing nutritional support truly influences recovery and outcome in humans as well as in veterinary patients.
