Specific dynamic action (SDA)

 Specific dynamic action (SDA)

Specific dynamic action (SDA), also known as thermic effect of food (TEF) or dietary induced thermogenesis (DIT) is the amount of energy expenditure above the basal metabolic rate due to the cost of processing food for use and storage. It is also called the cost of metabolism.

Heat production by brown adipose tissue 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 along with resting metabolic rate and the exercise 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 is very easy to process and has very little thermic effect, while protein is hard to process and has a much larger thermic effect. This is the waste heat not used in many body functions.

The thermic effect of food is increased by both aerobic training of sufficient duration and intensity or by anaerobic weight training. 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 intakes for the days are equivalent.TEF lasts beyond six hours for the majority of people.

Types of food- 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 as is shown in the table below-

Type of Food Item	% of the energy consumed
Carbohydrates	5 to 15
Protein	20 to 30
Fats	5 to 15

 

Significance- Body fat loss and consequent weight loss depends upon the type of food one consumes, a diet with higher protein intake causes more weight loss due to higher SDA then a diet predominantly rich in carbohydrate.

Therefore after knowing the composition of food item a diet can be tailor made to suite the goal of an individual- whether it is weight loss or weight gain.