Metabolic adaptation to malnutrition

Resting and nonresting energy expenditure are reduced in restricted volunte ers. This decrease is due to fat-free mass depletion and also to a reductio n in energy expenditure per kilogram of fat-free mass. Protein deprivation leads to a reduction in protein turn-over or oxidation in the postabsorptiv e state and to a decrease in the amplitude of diurnal cycling of protein tu rn-over, synthesis and breakdown. Such a metabolic adaptation tends to main tain fat mass and to reduce the need for essential amino acids. In adults w ith naturally occurring states of malnutrition, the results vary according to the cause of malnutrition. One may observe or not a reduction in energy expenditure or protein metabolism. The lack of reduction of metabolic adpta tion could be due to the long term energy and protein deprivation and to th e preservation of visceral mass relative to muscle mass.