TOPIC 1 Flashcards
How much energy do carbohydrates provide the body?
16.7kj/g
How much energy do proteins provide the body per gram?
16.7kj/g
How much energy do lipids provide the body per gram?
37.7kj.g
How much energy does alcohol provide per gram? (remember that alcohol is not considered a macronutrient)
29.3kj.g
how do you calculate the composition of macronutrients?
Amount of macronutrients x by amount of energy that macronutrient provides
E.g a food that contains 76.2g of carbohydrates = 76.2 x 16.7 = 1272.54kj
how do you calculate the energy distribution formula?
Macronutrient energy/total energy of the food x 100
e.g
total energy of the food = 1446.14kj
carbs in a food = 1272.54kj
therefore, (1272.54/1446.14) x 100 = 87.9%
What is AMDR?
Acceptable macronutrient distribution range
It is the recommended balance of macronutrients for individuals of a healthy weight to reduce the risk of developing diet-related disorders
What is the AMDR for carbs, fat and protein?
carbs = 45-65%
Fat = 20-35%
Protein = 15-25%
What is the formula to work out the amount of energy provided by alcohol?
(10g x standard drink) x 29.3kj
e.g
Can of beer = (10x0.8) x 29.3 = 235/4kj
Red wine = (10x1.6)x29.3 = 468.8kj
Define positive and negative energy balance.
Positive energy balance:
Energy intake > energy expenditure, leading to weight gain.
Negative energy balance:
Energy intake < energy expenditure, leading to weight loss.
What are the three things that determine someone’s energy expenditure?
- Energy expended for basal metabolic rate
- Energy expended for physical activities
- Energy expended for food digestion (thermic effect of food)
What is Basal Metabolic Rate?
the rate at which the body expends energy for basal metabolic activities that support all basic processes of life.
What are some factors that affect BMR?
- Body composition: A larger amount of lean body tissue increases BMR because muscle tissue metabolises faster than adipose tissue
- Growth: During childhood, adolescence and pregnancy, energy demands are greater due to the growth experienced, increasing their BMR
- Age: Lean body mass diminishes after the age of 30, and the time available to complete physical activity declines which can contribute the the decline in BMR
- Gender: Males generally have a higher BMR as their body is composed of greater lean body tissue than females. Males also expend more calories per kilogram per hour than females. Where males burn 1.0 calories, females burn 0.9
What is the BMR formula for males and females?
Males: BMR (kJ) = Body weight (kg) x 1.0 x 24 hours x 4.2
Females: BMR (kJ) = Body weight (kg) x 0.9 x 24 hours x 4.2
How do you calculate the Thermic Effect of Food?
To calculate the thermic effect of food you calculate 10% so:
0.10 x ___kJ consumed/day
E.g 0.10 x 8500kJ consumed/day = 850kJ
How do you calculate estimated energy expenditure?
EEE (kJ) = BMR (kJ) + TEF (kJ) + energy expended through physical activity(kJ)
How do you calculate energy balance?
Energy balance (kJ) = daily energy intake (kJ) – daily estimated energy expenditure (EEE) (kJ)
What is the recommended daily intake (RDI)
The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all healthy individuals
What is adequate intake (AI)
The average amount of nutrients that a group of healthy individuals requires. Used when EAR can not be determined
what is the tolerable upper intake level?
The upper level is the amount that, if exceeded can be toxic
What is the Estimated energy requirement (EER)?
The average dietary intake (kj/day) required to maintain energy balance. Used by individuals of a healthy weight and activity level
Identify the general structure and sources of simple carbohydrates
Monosaccharides and disaccharides can be called simple carbohydrates (sugars).
They consist of one or two sugar units which contributes to them being easily absorbed by the body and can cause increased spikes in blood glucose levels
Identify general monosaccharide structure and types of monosaccharides
- 3 monosaccharides which consist of one singular sugar unit
-Each contains 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms which can be written in shorthand like C6H1206
-Cannot be broken down further as already only 1 sugar unit
-Monosaccharides serve as the building blocks for all other sugars and carbohydrates
3 monosaccharides include
- Glucose
- Fructose
- Galactose
Identify general structure and types of disaccharides
Simple sugars made up of two monosaccharides joined together.
Digestion requires only one bond between the two sugar units or monosaccharides to be broken, allowing for quick absorption and release into the bloodstream
There are 3 disaccharides which include:
- Maltose (glucose + glucose)
- Sucrose (Glucose + fructose)
- Lactose (Glucose + galactose)
Identify general structure and types of complex carbs
Oligosaccharides and polysaccharides
They can be ‘larger’ in size and consist of 3 or more singular sugar units (monosaccharides) joined together to form chains
The breakdown of these carbs into monosaccharides takes much longer and is dependent on the number of sugar units it is composed of.
Therefore these carbs are absorbed into the bloodstream alot slower, contributing to a steady rise in blood glucose levels.
Identify general structure and sources of Oligosaccharides
Complex carbs composed of 3-10 singular units.
Oligo means just a few.
These carbs are not relatively abundant in the diet when compared to other classifications
Examples include: Raffinose
Identify general structure and sources of Polysaccharides
complex carbs which consist of more than 10 singualr sugar units.
Poly means many. T
these are the most abundant in foods
- Starch
- Resistant starch
- Glycogen
- Soluble and insoluble fibre
Explain the effects of different carbohydrates on blood glucose (blood sugar) levels.
Simple Carbs: Monosaccharides and disaccharides are absorbed quickly, causing a rapid rise in blood glucose levels. These foods have a high glycaemic index (GI).
Complex Carbs: Starches break down slowly, leading to a gradual increase in blood glucose levels and sustained energy. These foods have a low glycaemic index (GI).
Identify sources of soluble fibre
- Oats
- Legumes
- Fruits
- Vegetables
Identify sources of insoluble fibre
- Whole grains
- Vegetables
-Fruits
-Legumes
Explain the role of soluble fibre in the body and its role in the prevention of some diet-related diseases
- binds with water and partly dissolves forming a thick gel-like substance in the stomach, the gel expands providing the feeling of satiety.
-slows release of food from the stomach into small intestine slowing digestion allowing for gradual absorption of nutrients. This can also help to regulate blood glucose levels, preventing the onset of type 2 diabetes
- helps regulate blood sugar and cholesterol levels by binding to bile acids in the small intestine. This binding reduces the reabsorption of cholesterol into the bloodstream, lowering the risk of cholesterol buildup in artery walls, which can lead to atherosclerosis. The bound bile acids are then carried through the digestive tract and excreted as waste.
Explain the role of insoluble fibre in the body and its role in the prevention of some diet-related diseases
adds bulk to stool aiding digestion and preventing constipation.
Both types of fibre are crucial for preventing heart diseases, diverticular disease and diabetes by regulating blood sugar and cholesterol levels and promoting healthy digestion
What are triglycerides and what is the basic structure?
the most abundant lipids, both in foods and the body.
Every triglyceride is composed of glycerol, which acts as a backbone to three attached fatty acid chains.
Identify and compare the general structure and sources of the following fatty acids:
o saturated
Has all its hydrogen atoms and contains only single bonds between carbon atoms
Generally at room temperate and have a higher melting point
Identify and compare the general structure and sources of the following fatty acids:
o unsaturated
Does not contain the full amount of hydrogen atoms, due to containing at least one double bond between carbon atoms
Identify and compare the general structure and sources of the following fatty acids:
o monounsaturated
contains one double bond between the carbon atoms
generally liquid at room temperature and have a lower melting point than saturated fats
Identify and compare the general structure and sources of the following fatty acids:
o polyunsaturated
that contains more than two double bonds between the carbon atoms is a polyunsaturated fatty acid.
generally liquid at room temperature and have a lower melting point than saturated fats and monounsaturated fats
Identify and compare the general structure and sources of the following fatty acids:
o trans fatty acid
Naturally occurring trans fatty acids have double bonds with hydrogen atoms on opposite sides of a straighter carbon chain, unlike cis fatty acids, where hydrogens are on the same side, causing a bent shape
.
Comparison: Trans fats are more solid at room temperature, similar to saturated fats, despite having a double bond.
What is the process that trans fatty acids are generally made from?
hydrogenation therefore AKA hydrogenated fats.
During hydrogenation, some or all (double bonds) are made saturated by breaking the double bonds and adding hydrogen atoms.
Most often, polyunsaturated fatty acids are partially hydrogenated. the double bonds that remain after processing change configuration from cis to trans where the hydrogen atoms at the double bond are now on opposite sides of carbon chain.
During complete hydrogenation, all the double bonds are broken and are saturated with hydrogen atoms. This process converts unsaturated fatty acids to saturated fatty acids.
The benefit of hydrogenation is it can improve the texture of foods by making them more solid and protecting fats against oxidation, which causes these products to turn rancid.
Explain the functional roles of triglycerides as a nutrient
Transportation and Storage of Fat-Soluble Vitamins:
- Triglycerides transport and store fat-soluble vitamins (A, D, E, and K) and cholesterol.
- During digestion, these molecules congregate with triglycerides, forming lipoproteins to travel through the bloodstream.
- The lipoproteins deliver these nutrients to adipose tissue, where they are stored until needed.
Source of Energy:
-Triglycerides are the primary energy storage molecules.
-When energy is needed, they break down into glycerol and fatty acids, carried via a protein (albumin) to cells requiring energy.
-Triglycerides are energy-dense, providing 37kJ/g, and should make up about 30% of daily energy intake.
Cushioning and Insulation of Vital Organs:
-Triglycerides stored in adipose tissue act as cushioning around vital organs (visceral fat) and under the skin (subcutaneous fat).
-Visceral fat protects organs and joints, while subcutaneous fat aids in thermoregulation, reducing heat loss through the skin.