Origins of emaciation in cancer patients.

Anorexia and elevated energy expenditure contributes to weight loss in cancer patients. Increased energy expenditure may explain 0.5-1.0 kg weight loss per month with regard to resting energy expenditure and even more with regard to total energy expenditure. The explanation behind elevated energy expenditure does not seem to be due to the tumour metabolism itself but rather to an increased host metabolic demand aimed at providing life-supporting protein synthesis and perhaps the immune system with energy. The trigger behind the activation of the synthesis of certain proteins is unknown. Only sparse information is available on the altered regulation of appetite in cancer disease. Changed metabolism and activity of neurotransmitters seem to be involved.