1.1 Energy in Foods Flashcards
Catabolism
breaks down molecules into smaller units
- these are oxidised to release ATP or used by cells (anabolic reaction).
- E.g. complex carbs –> glucose
Anabolism
- construct molecules from smaller units endergonic process
- energy stored in fats cells or used to build or repair.
- E.g. lipids building cell membranes, proteins building tissues
The body requires energy for:
- Heat energy - maintaining body temp
- Electrical - in nerve cells
- Mechanical - for muscle
- Chemical - used in digestion/metabolism
Energy storage occurs in:
Glycogen/triglycerides (fat)
Macronutrients
- carbohydrates, lipids & proteins
- required daily in large amounts
- measured in g
Micronutrients
- vitamins/minerals
- Small amounts
- Work in conjunction with macros and each other
1 gram =
1000 milligrams, 1 mili = 1000 micro
Energy values
Carbohydrates: 16.7kJ/g
- Dietary fibre 8kJ/g
Protein: 16.7kJ/g
Lipids: 37.7kJ/g (are energy dense)
Alcohol: 29kJ/g (provides energy, no nutrients)
Energy Dense
Amount of energy or calories in a particular weight of food
- lower energy density foods - provide fewer kJ/g.
Energy Distribution of Macros (EDM): Carbs
Carbs: 45-46% of energy intake
- most should be complex
- 10-15% maximum of simps
- a minimum of 25g in dietary fibre
Energy Distribution of Macros (EDM): Protein
15-20% of energy intake
Energy Distribution of Macros (EDM): Lipids
20-30% of energy intake
- sat only 10%, less than 1% trans
To work out Energy Balance:
Calculate energy intake and expenditure
If intake > expenditure
Person will store energy –> gain weight
If intake < expenditure
Person will burn energy –> weight loss
If intake = expenditure
Maintain weight
Basal Energy
the minimum amount of energy used to maintain body temp and muscle tone to keep proper organ function.
BMR
the rate at which energy is expended.
Females and male BMR body weight factor
F: 1kg for bodyweight burns 0.9cal / h
M: 1kg of body weight burns 1.0cal / h
BMR Effecting Factors
body size - larger –> more metabolsing tissue greater BMR
age - metabolism slows due to muscle tissue loss
Infection - increase BMR to build new tissues or cause immune response
Calculate BMR
weight (kJ) x rate at which body burns calories x 24/h
to convert to kJ: x 4.2
Thermic Affect
energy used in digestion, absorption, and storage of ingested nutrients.
- contributes 10% of energy intake
- peaks 2-3 hours after eating
- Hot foods can have a significant thermal effect
How do macros affect BMR?
Lipids raise BMR 0-5%
Carbs raise BMR 5-10%
Lipids raise BMR 20-30%
Calculate Thermal Effect
10% of daily kJ consumption
