It is an amount of energy burned from any kind of physical activity. Physical activity can be Walking, Running, Cycling, or a heavy intense workout. The total amount of calories burned from these physical activities is known as the Thermic Effect Of Activity.
The best example to understand
Suppose your daily caloric intake is 3000 and you work out 5-6 times a week. Your workouts are very intense and you burn around 400 calories from your workout. Then your total calories per day including your activity will be 2600.
In the first place, the Thermic Effect Of Food is the caloric cost of digesting and processing different macronutrients in your diet. The caloric cost of protein is different from that of carbohydrates and fats. Moreover, the amount of macro that we eat in a day gets digested in our body and for that digestion, some percentage of macros are burnt.
As a matter of fact, 20-30% of PROTEIN calories are burnt digesting it. Many people think that if they intake 200 calories from protein, then their body will absorb a total of 200 calories.
For example, If you intake 200 calories from protein; 40-50 calories will burn to digest it.
2. 5-10% of CARBOHYDRATES calories are burnt digesting it. After all, the same is the case with carbohydrates. Therefore, the total calories consumed from carbohydrate is not fully absorbed by our body.
For example, If you intake 200 calories from carbohydrates; 10-20 calories will burn to digest it.
3. Similarly, 0-3% of FATS calories are burnt digesting it. Of course, we know that fat contains 9 calories per gram. But all 9 calories are not absorbed as some percentage burns just for digesting it.
For example, If you intake 200 calories from fats; 0-6 calories will burn to digest it.
The formula to calculate the Thermic Effect Of Food (TEF) is: