This document discusses energy expenditure and its components. There are three main components that make up energy expenditure: basal metabolic rate (BMR), the thermic effect of food (TEF), and physical activity. BMR accounts for 60-70% of total energy expenditure and is the minimum energy needed for essential functions. TEF accounts for 5-10% and is the energy used to digest and absorb food. Physical activity accounts for 20-40% and varies based on daily activities. The document provides equations to estimate BMR and describes factors that influence energy expenditure components.

1. Energy
expenditure

2. Energy expenditure
• Your energy expenditure is simply the number of
calories your body uses.
• Energy requirements are the amount of food energy
that should be eaten to compensate for caloric
expenditure.
• It’s important to learn these
energy requirementes to
have a good energy balance.

3. Energy expenditure
• If you know a little bit about your energy expenditure
and approximate metabolic rate, you can give a picture
of about how much you should be eating in a day.
• It’s important that the estimates of
the energy requirements may be for
long periods of time. There’s great
variability among these needs every
day.

4. Components of Energy
Expenditure
• There are 3 main components that make up your energy
expenditure:
1. Basal metabolic rate (BMR): energy needed to maintain
essential physiological functions, including growth,
pregnancy, lactation…
2. The thermic effect of food (TEF): Thermogenesis
necessary for digestive and metabolic utilization of nutrients.
3. Physical activity: energy for muscle contraction and
movements.

5. % of total energy
expenditure
Physical
Activity
20-40%
Basal Metabolic
Rate 60-70%
Thermic Effect
of Food 5-10%

6. Basal metabolic rate
(BMR)
• Amount of minimum energy needed to maintain essential
physiological functions and homeostasis.
• It would be equivalent to the energy expenditure that is during
quiet sleep.
• Total energy expenditure is similar to the basal although
somewhat higher (approx. 10%).
• It represents 2/3 of the daily consumption of energy. It
represents the 60-70% of the energy expenditure.
• This closely related to lean or fat-free mass. Adipose
tissue is metabolically active low

7. Factors that influence
basal metabolic rate
• Size and body surface, logically increases to larger size of
organs.
• Sex and body composition: the man
is metabolically more active. The
woman has approximately 10% of
fat than man.
• Age: every 10 years the basal
metabolic rate decreases 3-5% from
age 20.
• Pregnancy and lactation: in the last two trimesters of
pregnancy, there is an increase in metabolism (200-300 kcal /
day)
• Other: Fever, Balance hormonal diseases, drugs, growth

8. How you calculate your
BMR?
• Fast estimation equation:
24 Kcal/ hora/ Kg de peso
♂MB= 1,0 kcal/ h/ kg
♀MB= 0,9 kcal/ h/ kg
• Mifflin St. Jeor (1990) equation:
♂ MB = [9,99 x weight (kg)] + [6,25 x height (cm)]
– [4,92 x age (years))] + 5
♀MB = [9,99 x weight (kg)] + [6,25 x height (cm)]
– [4,92 x age (years))] - 161

9. The thermic effect of
food (TEF)
• Amount of energy for food digestion and absorption
and metabolism of nutrients.
• This energy expenditure ranges around 5-10%, although
it depends on the content of nutrients in the diet.
• Varies from one individual to
another, and in the same
individual for a few moments to
others.
• So will vary in a hyperproteine diet, hyperlipidemia diet
or rich in carbohydrates diet.

10. Physical activity
• Normally represent between 20-40% of the energy
expenditure.
• It can vary significantly between individuals on the basis of the
deployed activity. It is not constant and depends on daily
physical activity. Some individuals may be twice the basal
metabolic rate.
• It is the most variable component, so that certain types of
exercise, where there is a great physical activity, can be used
in multiple times increases of resting energy expenditure

11. There are different situations and factors that lead to
changes in the absolute values of the energy expenditure
by physical activity, which includes the following:
• Physical activity: the intensity and duration of physical
activity are the key factors in determining energy
expenditure by physical activity, as well as the frequency.
• Body weight, increased weight, increased energy
expenditure by physical activity, since it takes more
energy to move more weight.
• Age, aging tends to lead to less physical activity, this fact
coupled with a lower basal metabolism, does that energy
demands decrease significantly.
• Climate, may condition the physical activity in significant
degree. This is particularly evident in extreme, both cold
and hot climates that they do to reduce physical activity
outside the home and condition maintenance of body
temperature.

12. How you calculate your
physical activity
expenditure?
• There are tables that collected by physical activity
expenditure expressed in kcal/kg of weight and time.
• It’s simple, you must multiply the variable by the number
of minutes
• For example:
Study: 0,02 x 60 min= 1,2
Dance: 0,07 x 35 min= 2,45
Physical activity expenditure = 3,65 kcal

13. How you calculate your
physical activity expenditure?

14. References
• Bouchard, C., Tremblay, A., Leblanc, C., Lortie, G.,
Savard, R., & Theriault, G. (1983). A method to assess
energy expenditure in children and adults. The American
journal of clinical nutrition, 37(3), 461-467.
• Mifflin, MD, St. Jeor, ST, Colina, Los Ángeles, Scott, BJ,
Daugherty, SA, y Koh, YO (1990). Una nueva ecuación
predictiva de gasto energético en reposo en individuos
sanos. American Journal of Clinical Nutrition , 51 (2),
241-247.