Energy Flashcards
What is metabolisable energy?
Is digestible energy ingested that is not recoverable as gross energy in lost hair, skin , breath and urine. (Livesey et al, 2000)
What are the three components of energy expenditure?
BMR, thermogenesis, and physical activity.
What is BMR?
Standardised conditions i.e. awake lying in the supines position at physical and mental rest in comfortable warm environment in the morning, usually 10 to 12 hours after last meal
What is gross energy?
Is heat energy that can be released by complete combustion and is the same as the heat of combustion when expressed per-unit weight of combusted material. (Livesey et al, 2000)
What is digestible energy?
Is gross energy ingested that is not recoverable as gross energy lost in the faeces and flatus (methane and hydrogen).
What is “net metabolisable” energy?
It is metabolised energy ingested that is not wasted as heat or the heat of fermentation and heat of metabolism spent in yielding “high energy” bond equivalents. (Livesey et al, 2000)
What is the % of digestible energy for carbohydrates?
99%
what is the percentage of digestible fat?
96%
What is the percentage of digestible protein?
92%
Who validated and derived metabolisable energy equivalents for energy for protein, fat and carbohydrate?
Atwater (1902)
What is the calculation for digestible energy?
Digestible energy equals energy intake minus faecal energy multiply by100 divided by energy intake
Give values for metabolisable energy of food
4 kcal/g CHO
4 kcal/g protein
9 kcal/g fat
7 kcal/g alcohol
Give values of digestible energy of foods.
4 kcal/g CHO
5.2 kcal/g protein
9 kcal/g fat
7.10 kcal/g alcohol
What is the relative percentage contribution of BMR,thermogenesis and PAL?
BMR 60 to 75%
PAL 15 - 30%
Thermogenesis 10%
Explain what is meant by dispensable and indispensable amino acids.
Essential or indispensable means nutrient must come From diet the body cannot make the nutrient.
Dispensable means the body can make the nutrients.
List nine indispensable amino acids.
Hill PMT TV
Histidine, isoleucine, Leucine, lysine, phenylalanine, methionine, tryptophan, threonine, valine.
What is biological value?
A measure of how much nitrogen is retained from a test source of protein by the body for maintenance and growth once absorbed as opposed to just the total amount absorbed. (Gripper & Smith,2012)
How do complimentary proteins increase biological value?
By combining food sources that are low in one amino acid virsus another
What is gross energy?
Gross energy is the heat that can be released by complete combustion.
What is the protein efficiency ratio (PER)?
PER equals Weight gained divided by weight of protein consumed
Where is PER used?
Often in dietary supplement industry to make claims regarding growth potential of a protein powder
What does a high bv value mean?
The body retains much of the absorbed nitrogen e.g. eggs have a bv of 100 meaning that 100% nitrogen absorbed from the protein is retained.
How is the bv determined?
Subjects fed nitrogen free diet and then test protein in an amount equal to their protein requirement. Then nitrogen excretion from both diets compared to see how much is retained of the test protein.
What are the limitations of bv studies?
Failed to account for losses of nitrogen through skin, hair nails.
Proteins exhibit high bv when fed at levels below levels for nitrogen equilibrium, and retention decreases as proteins exceeds needs.
