Energy requirement calculation *** Flashcards
What are the key elements of the Total Energy Expenditure (TEE) in healthy subjects?
- Resting Energy Expenditure (REE): About 60% of TEE.
- Activity induced Energy Expenditure (AEE): About 30% of TEE.
- Diet induced Energy Expenditure (DIT or TEF): About 10% of TEE.
What is the primary component of total energy expenditure comprising 60–70%?
Basal Metabolic Rate (BMR).
What is a product of mainly the metabolism of lean body mass and is therefore dependent on variables related to it, such as body weight, height, sex, and age?
Resting Energy Expenditure (REE) or Basal Energy Expenditure (BEE).
What is the energy required to thermoregulate and respond to changes in the environmental temperature, that comprises 10–15% of total energy expenditure?
Adaptive thermogenesis.
What percentage of the TEE is comprised by the diet induced thermogenesis (DIT)?
10–15%
What is the most variable component of total energy expenditure, and accounts for 15- 50% of TEE?
Activity induced energy expenditure.
What is considered the gold standard to measure caloric needs?
The calculation of heat production from chemical processes.
Which type of calorimetry involves measuring energy expenditure through the measurement of the production or loss of heat by the use of a ventilation hood and a respiration chamber to continuously measure VO2 and VCO2?
Direct calorimetry.
Which type of calorimetry involves the measurement of heat production by measuring O2 consumption and/or production of CO2 (both in mL/min)?
Indirect calorimetry.
What is the respiratory quotient used for?
To evaluate substrate utilization.
What are the different parameters of the respiratory quotient?
- Normal: 0.7-1.0.
- ≥1.0: May indicate excessive CO2, lipogenesis, and overfeeding.
- ≤0.7: May be due to metabolic or technical causes.
What are the most famous prediction equations for the calculation of TEE?
The Harris-Benedict, Ireton-Jones and Mifflin-St Jeor formulas.
When is the rule-of-thumb used for the calculation of TEE?
If the usage of indirect calorimetry is impossible, or the use of predictive equation is not feasible.
What is the rule-of-thumb?
- 20-25 kcal/kg of weight for overweight patients.
- 30 kcal/kg of weight for patients with normal weight.
What components are the principal source of energy in a normal diet (particularly during anaerobic exercise), and comprise 40–55% of energy requirements in the Western diet?
Carbohydrates
What components represent the major form of energy storage in the body, with high content of energy and low hydration?
Dietary lipids.
How much energy do dietary lipids contain?
1 g of triglyceride carries 9.3 kcal.
What are the three types of dietary fatty acids?
- Saturated
- Monounsaturated
- Polyunsaturated
What are the three types of aminoacids?
- Non-essential amino acids.
- Conditionally essential amino acids.
- Essential amino acids.
What is an example of a conditionally essential amino acid?
Glutamine, which may become essential in certain disease states if the requirement for particular amino acids is increased.
What are the recommendations for carbs, fat and protein regarding their involvement in the TEE?
- Carbs (CHOs): 40-55% of total energy, 50% of TEE, less than 10% from sugar.
- Fat: 25-35% of total energy, 30% of TEE, less than 10% from saturated fatty acids.
- Protein: 15-20% of the total energy, 20% of TEE.
What’s the energy content of carbs, protein and fat?
- 1 g carb = 4 kcal
- 1 g prot = 4 kcal
- 1 g fat = 9 kcal
What are the four methods of calculating the energy requirements?
- Direct calorimetry.
- Indirect calorimetry.
- Prediction equations.
- Rule of thumb.
What is the Harris-Benedict equation for men?
BMR = 88.362 + (13.397 ⨯ weight in kg) + (4.799 ⨯ height in cm) - (5.677 ⨯ age in years)
What is the Harris-Benedict equation for women?
BMR = 447.593 + (9.247 ⨯ weight in kg) + (3.098 ⨯ height in cm) - (4.330 ⨯ age in years)
Which prediction equation created in the 1990s provided a valid estimate of RMR?
The Mifflin-St Jeor formula.
Which prediction equation revised by Roza and Shizigal in 1984 provided a valid estimate of BMR?
The Harris-Benedict equiation.
What is the Mifflin-St Jeor formula for men?
RMR = (10 ⨯ weight in kg) + (6.25 ⨯ height in cm) - (5 ⨯ age in years) + 5
What is the Mifflin-St Jeor formula for women?
RMR = (10 ⨯ weight in kg) + (6.25 ⨯ height in cm) - (5 ⨯ age in years) - 161
