Thermogenic effect and physical activity

Energy expenditure

In this topic we will see how the thermogenic effect of food and physical activity influence the energy expenditure of an individual, which is nothing more than the relationship of balance that must be established between the energy we consume daily and the energy necessary for the correct functioning of all the functions of the organism.

Thermogenic effect of food

The thermogenic effect of food (ETA), thermogenesis or dynamic-specific action of food, refers to the energy consumption that takes place in the body due to the production of heat during the ingestion and digestion of food, accelerating the metabolism. In a simpler way, it can be said that your body burns calories by digesting the different nutrients you ingest.

This effect is different for the three macronutrients (proteins, carbohydrates and fats), depending on the differences in the storage and absorption process of the nutrients. For example, the energy expenditure of protein digestion is higher than that of fats, since it is necessary to transform glucose and amino acids into glycogen and protein. Let us now see what is the percentage increase in heat production by each of the macronutrients:

• Proteins-12%.

• Carbohydrates-6% Fat-2%.

• Fats-2%.

This means that if you consume 200 calories of pure fat, your body will use 4 of those calories for digestion.

Generally speaking, it is accepted that thermogenesis accounts for approximately 7% to 10% of the total energy consumed from food in a mixed diet.

Physical activity

Physical activity energy expenditure refers to the energy consumed for the performance of any voluntary activity, whether it is working, exercising or simply walking.

The increased energy expenditure does not only occur during the precise moment of exercise, but continues after it has been performed, and several factors are involved, such as the type of activity, the time spent, body weight, among others. Because of this, physical activity is the most variable component of daily energy expenditure, varying from 10% in sedentary people to 40% in very active people. At the same time, it is the variable that the individual can most easily control to modify total energy expenditure.

There are several ways of calculating energy expenditure by physical activity, some of which are expressed as kcal/kg since, in general, weight is related to energy expenditure. However, this is not always advisable, as there are activities in which this factor is nullified by the body resting on a surface or some other similar circumstance.

This energy expenditure can also be expressed in physical activity levels, or PAL (Physical Activity Level), which is nothing more than the result of dividing the total energy expenditure, or TEE (Total Energy Expenditure), which refers to the energy consumed by a person in a 24-hour radius, and the basal energy expenditure (BEE), which would be the metabolic expenditure of a person at rest, for which there are formulas tha