Diet induced thermogenesis ,or the thermic effect of food(TEF),is the increase in energy expenditure above RMR that occurs for several hours after ingestion of a meal. Diet Induced Thermogenesis is the result of digestion, absorption, metabolization, and storage of food and normally represents about 10% of total daily energy expenditure. The magnitude of Diet Induced Thermogenesis depends on several factors, including the energy content of the food and the size and composition of the meal. Diet Induced Thermogenesis also depends on the metabolic fate of the ingested substrate.
The cost of storing fat in adipose tissue is approximately 3% of the energy of the ingested meal, whereas if carbohydrate is stored as glycogen, about 7% of the energy is lost. The energy cost for the synthesis and breakdown of protein is approximately 24% of the available energy.
Energy expenditure can be increased up to 8 hours.The sympathetic nervous system seems to play an important role in Diet Induced Thermogenesis. When the effects of the sympathetic nervous system are reduced by administering aft adrenergic blocker (e.g.,propranolol), Diet Induced Thermogenesis is also reduced. With increasing age there is as mall decline in Diet Induced Thermogenesis. This might be associated with a decrease in insulin sensitivity.
Diet induced thermogenesis ,or the thermic effect of food(TEF),is the increase in energy expenditure above RMR that occurs for several hours after ingestion of a meal. Diet Induced Thermogenesis is the result of digestion, absorption, metabolization, and storage of food and normally represents about 10% of total daily energy expenditure. The magnitude of Diet Induced Thermogenesis depends on several factors, including the energy content of the food and the size and composition of the meal. Diet Induced Thermogenesis also depends on the metabolic fate of the ingested substrate.
