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Macronutrients - fat

Macronutrients: Fat
3.2 Food, nutrition and health
3.2.1 Macronutrients – Fats
This section relates to the topic of food and nutrition. It moves on to the macronutrient
fats. The functions and uses of fats in the body are explored as well as the different types
of fats. The dietary reference values (DRVs) are also covered and the problems of excess
or deficiency of fats.
Copy this homework in your planner
Create a table and Identify 20 HBV and LBV
List 10 protein complementation dishes
Title: Macronutrients
Learning objectives:
• Can you explain the functions of fat in the diet?
• Can you name the food sources of fat in the diet?
• Can you recall the maximum amount of fat recommended in our
diet to stay healthy?
• Can you describe the terms saturated fat, monounsaturated
fat and polyunsaturated fat?
• Can you describe the effects of a deficiency and excess of fats?
• Saturated
Saturated fat
Invisible fat
• Polyunsaturated
Unsaturated fat Triclyceride
• Monounsaturated
Fatty acid
Visible fat
Put the following food in the correct category: saturated
fat or unsaturated fat
Sunflower oil
olive oil
rapeseed oil
What is fat?
What is fat?
• Fat is a micro nutrient that is needed by all animals. The
term fats can be fat or oils. Fats are solid at room
temperature while oils are liquid at room temperature.
• Both fats and oils have the same chemical structure and
also provide the same amount of energy.
What is the chemical structure of fat?
Basic structure of fat and oil
 Fats are made up of unit of glycerol and
three fatty acids like this;
Fatty acid 1
Fatty acid 2
Fatty acid 3
This molecule is called triglyceride. Fatty
acids are made up of carbon and
hydrogen. And they can be saturated
(monounsaturated) fat or unsaturated
Type of fat: Saturated fat
 They are known as unhealthy fat and
they are solid at room temperature.
They are mainly from animal such as
meat and processed meat like
burger, sausage, suet and cheese.
They can also come from plant like
coconut butter. Eating too much of
this fat can increase cholesterol levels
in the blood and this can increase
the risk of coronary heart disease.
Types of fat: unsaturated fat
 They are known as healthy fat and
they are liquid at room temperature.
They are mostly from vegetables that
are high in fat such as flax seeds and
peanuts and vegetable oil such as .
Sunflower oil, olive oil, rapeseed and
some others.
 Unsaturated oil can either be
monounsaturated or
Monounsaturated fats
 Monounsaturated fat is a type of dietary fat. It is one of the healthy fats,
along with polyunsaturated fat. Monounsaturated fats are liquid at room
temperature, but start to harden when chilled. The fats are healthy
fats found in olive oil, avocados and certain nuts. In fact, the evidence
shows that monounsaturated fats have a number of health benefits. They
can help with weight loss, reduce the risk of heart disease and decrease
Monounsaturated fatty acids
Monounsaturated fatty acids have one
carbon – carbon double bond and they do
not provide us with essential fats – avocados
are a source of monounsaturated fat.
Examples of foods high in monounsaturated fats include
plant-based liquid oils such as:
 Olive oil,
 Canola oil,
 Peanut oil,
 Sunflower oil and.
 Sesame oil.
How is fatty acid broken down?
 When we eat food that contains fat, our body breaks
down the fat molecules in the food and make new
fatty acids and fat molecules mainly for the body to
 However, our body can’t produce two of the fatty
acids and we have to eat food that will provide
them. Hence, they are refer to as essential fatty acids
because both children and adults needs them. They
are mainly found in an oily fish, plant and seeds oils,
eggs and fresh meat.
Polyunsaturated fat
The fatty acids has more than one unsaturated carbon
bonds and more than one carbon-carbon double bonds.
It provide us with essential fats such as omega 3 that
the body cannot produced..
Why do we need to eat fat in our diet?
Hydrogenation of fats
 When fats are hydrogenated, double bonds
become single bonds so that the carbon
atoms are saturated with hydrogen atoms.
The functions of fats
Our body needs fats for the following reasons:
1. To make cholesterol which is an essential part of our cell
2. To provide a store of energy in the adipose tissue under
the skin– 1g of fat provides 9kcals of energy
3. To insulate our body and help it the body to stay warm
4. To protect our bones, brain and vital organs such as the
kidneys and so on from damaging
5. To provide the body with fat soluble vitamins such as
vitamin A, D, E and K
6. To provide the essential fatty acids
How much fat do you need?
• Fat should provide no more than 35% of food energy.
• 11% (maximum) of our energy intake should come from
saturated fat.
• Mono-saturated fatty acids 13%
• Poly-saturated fatty acids 6.5%
• Trans fatty acid 2%
Answer the following questions
What is fat?
What is the percentage of fat that should be consumed in our diet daily?
Why do can’t we remove fat from our diet?
Explain the difference between monounsaturated fat and polyunsaturated fat
Describe the structure of fat?
Explain the difference between the two groups of fat?
Hydrogenation of fats
 Hydrogenation is when vegetable oils are
‘hardened’ to make them solid at room
temperature. This allows oils to be made into solid
fat spreads and to be used to make pastries,
cakes and biscuits.
 Hydrogenated fats are thought to cause health
problems such as heart disease. Food
manufacturers are being encouraged to reduce
the amount of hydrogenated fat in food.
Hydrogenation of fats
Answer the following questions
 How much fat do we need to eat daily?
 What is the difference between saturated and unsaturated
 Give examples of monounsaturated fat
 Give examples of polyunsaturated fat
Deficiency of fat
 A lack of fat means less fat soluble
vitamins such as vitamin A, D, E and K
are less absorbed by the body and this
can lead to health issue.
 The body use energy from fat as an
alternative if it can get energy from
carbohydrate and this means if fat is
not eaten, it can lead to weight loss
 A diet without fat can make a person
to be cold easily(less insulator)
 The body can get bruised easily
because there will not be enough fat
to protect it (thin layer)
Excess fat
 Too much fat can lead to weight gain as
excess fat is stored under the skin
 It can lead to obesity
 It can lead to diet related health issue such
as diabetes
 It can increase cholesterol levels in the
blood vessel such as arteries and this can
increase high blood pressure, lead to stroke
or heart attack
Visible and invisible fats
• Fats can be visible in some foods, such as the fat
layer on the outside of lamb or pork.
• The fat in meat may also be shown as marbling,
which appears as white streaks or flecks of fat
within the meat flesh.
• Visible fat is also the butter on a slice of toast.
• Fats can be invisible and cannot be seen – for
example, the fat in pastries and cakes.
• Liquid foods such as sauces and gravy often
contain invisible fat.
Answer the following questions
How much fat do does we need to eat daily?
What is the difference between saturated and
unsaturated fat?
Why do we need to consume some fat in our diet?
What are the sources of fat?
What is the name given to excess fat in our diet?
Describe some symptoms of fat deficiency.
Describe some symptoms of excess fat
Give examples of monounsaturated fat
Give examples of polyunsaturated fat