Energy expenditure

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.

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.

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.

% of total energy expenditure

Physical Activity 20-40%

Basal Metabolic Rate 60-

70%

Thermic Effect of Food 5-10%

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

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

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

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.

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

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.

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

How you calculate your physical activity

expenditure?

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.