1.7 Fats
Fats are made up of the same elements as carbohydrates
– carbon, hydrogen and oxygen – but in different
proportions. They are found in both animal and plant
foods. Fats are a concentrated source of energy, with
1 gram of fat supplying 37 kilojoules of energy.
Other functions of fats include:
• making food more appetising
• carrying the fat-soluble vitamins – A, D, E and K
• providing essential fatty acids.
The diagram below sets out the percentage
of fat found in a range of foods.
Fats are triglycerides, formed from
three fatty acids and one glycerol
molecule. The fatty acids may
be saturated or unsaturated.
There are some fatty acids,
known as non-essential fatty
acids, that can be made by the
body. Essential fatty acids are
those that must be provided
by food, as the body cannot
make them.
The three main groups of fats
are described in the table following.
The consumption of high levels
of trans fats is not a major issue in Australia –
saturated fats are the major issue in Australia.
Fat =
fatty acids + glycerol
Most foods contain a mixture of each type of fat, but
are classified according to the fat of which they contain
the greatest percentage. Note that all fats provide the same
number of kilojoules.
Most of us would be surprised to know how much
fat we really consume. We are usually aware of fat in
butter, cream, margarine, oils and meats, yet we often
are oblivious to the fat that is hidden in biscuits, pastries,
cheese, chocolate, fried and takeaway foods, cakes, and
potato chips and crisps.
We need fat in our diet, but in our well-nourished and
under-exercised society, we tend to consume too much in
amount and too much of the wrong type of fat. A diet high
in saturated and trans fats can also be high in cholesterol and
lead to high levels of triglycerides in the blood. These can
in turn lead to diet-related diseases such as coronary heart
disease, high blood pressure, diabetes and gallstones. We will
explore these diseases in more detail on pp. 46 to 49.
Low-fat diets are not suitable for children under the
age of two years. Reduced-fat milk may be used from the
age of two years.
Percentage of fats found in foods
cheddar
cheese:
34%
Dairy foods
Spreads
Meat, fish and eggs
reduced-fat milk:
2%
mayonnaise:
25–75%
eggs: 12%
canned salmon:
chicken breast, raw:
8–10%
2%
white fish, raw:
canned tuna
1.5%
in brine: 2%
grilled bacon:
oily fish, raw:
22%
12–18%
lean mince, raw: lean red meat, raw:
10%
2–6%
full-cream
yoghurt: 4%
cream cheese:
33%
cream:
35%
butter:
81%
oil:
100%
margarine:
80%
Vegetables and fruit
Breads and cereals
Snacks
avocado:
23%
white flour:
1%
rice bran:
20%
potato crisps: 33%
potato chips:
coconut, desiccated:
14%
65%
rolled oats:
8%
doughnut:
21%
fruits:
trace
44
full-cream
milk: 4%
croissant:
24%
vegetables:
trace
brown rice:
1%
wheatgerm:
7%
cooked rice/pasta:
trace
chocolate cake:
18%
Licensed to Fiona Ritchie, from Siena Catholic College until 2021-01-01.
peanuts:
53%
corn chips:
27%
Unsaturated fats – the good
Do not contain the maximum
amount of hydrogen
•
•
•
•
Saturated fats – the bad
Contain the maximum amount
of hydrogen (i.e. they are
saturated with hydrogen)
•
•
•
Trans fats – the ugly
Created artificially
by a process called
‘hydrogenisation’ whereby
liquid oil is converted to solid
fat in order to obtain the
correct consistency
•
•
•
•
Classified as either monounsaturated or polyunsaturated
Often called ‘good’ fats because they can help decrease cholesterol
The Australian Guide to Healthy Eating recommends that these fats be consumed in small
amounts each day
Found in sunflower, olive and canola oils and margarines, as well as in many nuts, seeds,
fish and soy foods, such as tofu
Found in both animal and plant foods, including fatty meat, dairy products, palm and
coconut products, and commercially baked products
Tend to increase low-density lipoproteins (LDL) in the blood, which can elevate cholesterol
levels and therefore increase your chance of coronary heart disease
According to the Australian Guide to Healthy Eating, foods high in saturated fats are
‘discretionary food choices’ and are to be consumed sometimes and in small amounts,
because the link between consumption of saturated fats, blood cholesterol and
cardiovascular disease is well established
Considered most harmful to our health, but not found widely in Australian foods
Like saturated fat, trans fats increase the level of bad LDL cholesterol; trans fats also
lower the level of high-density lipoproteins (HDL) – or good cholesterol – in the blood,
which protects against coronary heart disease
May be found in foods such as pastries, cakes, biscuits, and in some deep-fried foods
and processed food, as well as naturally in some foods such as meats
Manufacturers in Australia are not required to include information about trans fats unless they
make a claim about unsaturated fats or cholesterol; if no claim is made, the manufacturers
are only required to include information on their label about total and saturated fats –
therefore, some foods can contain trans fats and not display that fact on the label
LET’S REVIEW
Let’s examine
5
1
How much energy is contained in 1 gram of fat?
2
Identify the various functions of fats.
3
Identify the two main types of fats found in Australian
foods and create a mind map to identify the main
differences between them.
4
Outline the health concerns associated with a diet high
in saturated and trans fats.
Fish burger ›› p. 204
Outline why we may be unaware of the total amount of
fat that we consume.
Let’s analyse
1
The promotion of low-fat foods in the 1990s has been
linked to the increase in overweight and obese people
today. Research the reasons why low-fat and fat-free
diets are not necessarily healthy and present your
information as a fact sheet.
2
Devise a list of ten tips for eating less saturated fat.
Grilled salmon with braised cabbage ›› p. 210
Licensed to Fiona Ritchie, from Siena Catholic College until 2021-01-01.
45