Specific dynamic action (SDA), also known as thermic effect of food (TEF) or dietary induced thermogenesis (DIT), is the amount of

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

expenditure above the

basal metabolic rate Basal metabolic rate (BMR) is the rate of energy expenditure per unit time by endothermic animals at rest.. In other words it is the energy required by body organs to perform normal It is reported in energy units per unit time ranging from watt ( ...

due to the cost of processing

food Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...

for use and storage. Heat production by

brown adipose tissue Brown adipose tissue (BAT) or brown fat makes up the adipose organ together with white adipose tissue (or white fat). Brown adipose tissue is found in almost all mammals. Classification of brown fat refers to two distinct cell populations with si ...

which is activated after consumption of a meal is an additional component of dietary induced thermogenesis. The thermic effect of food is one of the components of

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

along with

resting metabolic rate Resting metabolic rate (RMR) refers to whole-body mammal (or other vertebrate) metabolism during a time period of strict and steady ''resting conditions'' that are defined by a combination of assumptions of physiological homeostasis and List of typ ...

and the

exercise Exercise or workout is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardio ...

component. A commonly used estimate of the thermic effect of food is about 10% of one's caloric intake, though the effect varies substantially for different food components. For example,

dietary fat In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple ester ...

is very easy to process and has very little thermic effect, while

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

is hard to process and has a much larger thermic effect.Christensen, Peter
"What is the thermic effect of food?"
Retrieved March 28, 2005.

Factors that affect the thermic effect of food

The thermic effect of food is increased by both

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cellu ...

training of sufficient duration and intensity or by

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: *Adhesive#Anaerobic, Anaerobic ad ...

weight training Strength training, also known as weight training or resistance training, is exercise designed to improve physical strength. It is often associated with the lifting of weights. It can also incorporate techniques such as bodyweight exercises ( ...

. However, the increase is marginal, amounting to 7-8 calories per hour. The primary determinants of daily TEF are the total caloric content of the meals and the macronutrient composition of the meals ingested. Meal frequency has little to no effect on TEF; assuming total calorie intake for the days are equivalent. Some studies suggest that TEF may be reduced in patients with obesity, although research findings are mixed. A low TEF could potentially predispose to obesity by reducing energy expenditure and promoting a positive energy balance. Alternatively, the presence of a low TEF in many patients with obesity may be explained by insulin resistance, which can be related to excess dietary energy and vary in severity with the degree of obesity. Over time, chronic hyperinsulinemia could diminish the ability of cells to respond to insulin, promote adiposity and peripheral insulin resistance, and worsen the risk for type 2 diabetes. Some research shows that TEF may be more severely impaired in patients depending on the grade of insulin resistance, although some other studies have not reproduced that finding. The mechanism of TEF is unknown, although it may be related in part to increases in sympathetic activity induced by eating food. TEF has been described as the energy used in the distribution of nutrients and metabolic processes in the liver, but a hepatectomized animal shows no signs of TEF and intravenous injection of amino acids results in an effect equal to that of oral ingestion of the same amino acids.Chaprapani U. and Satyanaryana. Biochemistry, 4th Ed. Elsevier India, 2013

Types of foods

The thermic effect of food is the energy required for digestion, absorption, and disposal of ingested nutrients. Its magnitude depends on the composition of the food consumed: * Carbohydrates: 5 to 15% of the energy consumed * Protein: 20 to 30% * Fats: at most 5 to 15% Raw

celery Celery (''Apium graveolens'' Dulce Group or ''Apium graveolens'' var. ''dulce'') is a cultivated plant belonging to the species ''Apium graveolens'' in the family Apiaceae that has been used as a vegetable since ancient times. The original wild ...

and

grapefruit The grapefruit (''Citrus'' × ''paradisi'') is a subtropical citrus tree known for its relatively large, sour to semi-sweet, somewhat bitter fruit. The flesh of the fruit is segmented and varies in color from pale yellow to dark red. Grapefru ...

are often claimed to have negative caloric balance (requiring more energy to digest than recovered from the food), presumably because the thermic effect is greater than the caloric content due to the high fibre matrix that must be unraveled to access their carbohydrates. However, there has been no research carried out to test this hypothesis and a significant amount of the thermic effect depends on the

insulin sensitivity Insulin resistance (IR) is a pathological response in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia. Insulin is a hormone ...

of the individual, with more insulin-sensitive individuals having a significant effect while individuals with increasing resistance have negligible to zero effects. The Functional Food Centre at Oxford Brookes University conducted a study into the effects of chilli peppers and

medium-chain triglyceride A medium-chain triglyceride (MCT) is a triglyceride with two or three fatty acids having an aliphatic tail of 6–12 carbon atoms, i.e. a medium-chain fatty acid (MCFA). Rich food sources for commercial extraction of MCTs include palm kernel oil ...

s (MCT) on Diet Induced Thermogenesis (DIT). They concluded that "adding chilli and MCT to meals increases DIT by over 50% which over time may accumulate to help induce weight loss and prevent weight gain or regain". Australia's Human Nutrition conducted a study on the effect of meal content in lean women's diets on the thermic effect of food and found that the inclusion of an ingredient containing increased soluble fibre and amylose did not reduce spontaneous food intake but rather was associated with higher subsequent energy intakes despite its reduced glycaemic and insulinemic effects.J

Measuring TEF

The thermic effect of food should be measured for a period of time greater than or equal to five hours. The ''American Journal of Clinical Nutrition'' published that TEF lasts beyond six hours for the majority of people.

Factors that affect the thermic effect of food

Types of foods

Measuring TEF

References

Further reading