Download Diet and Fitness

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A balanced diet
Diet is the usual food and drink that each person consumes
and is a very important part of health.
A balanced diet means eating the right types of food in the
right amounts so that the body gets the nutrients it needs.
What are the seven nutrients needed in a balanced diet?
 carbohydrates
 minerals
 proteins
 water
 fats
 fibre
 vitamins
Which foods contain these nutrients,
and why are they important?
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Getting the amounts right
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Types of nutrients
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Nutrients in food
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Eating too little
Many people do not have access to enough food. A lack of
nutrients can result in malnutrition. Malnutrition is a major
health problem. It increases the risk of disease and early death.
There are several reasons
why people might not have
enough food, including:

natural disasters

poverty

war
A lack of just one specific nutrient can cause a deficiency
disease, like anaemia or scurvy.
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Eating too much
Eating too much means that the body consumes more
energy than it uses and so the excess starts to build up.
People who are very
overweight for their height
are said to be obese.
Currently, 17% of 15year-olds in the UK are
classified as being obese.
Obesity is a serious health problem as it affects the heart,
blood pressure and can lead to joint problems.
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Deficiency diseases
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Digestion
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The stomach
As food moves through the digestive system it is broken down.
Useful food molecules and water are absorbed into the body.
After food is swallowed, it enters the stomach. food enters
from the gullet
Two things happen to food in the stomach:
 the chemical breakdown of food begins
 microbes are destroyed.
muscle tissue
food leaves
the stomach
From the stomach, food enters the small intestine where
digestion is completed and the small digested food molecules
are absorbed into the bloodstream.
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The intestines
After the small intestine, the remains of the food travels
to the large intestine. All that is left of the food is water
and waste material.
The water is valuable, so it is
absorbed from the large
intestine into the bloodstream.
The waste material cannot be
digested or used by the body.
small
intestine
The undigested waste travels to the
rectum where it is stored until leaving
the body through the anus.
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large
intestine
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Organs of the digestive system
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What is digestion?
The body carries out digestion of food to convert large
insoluble food molecules into smaller soluble ones.
carbohydrate
molecule
protein
molecule
fat
molecule
Large food molecules cannot pass through the walls of the
small intestine. Small food molecules can do this when
dissolved in the bloodstream. Why is this important?
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What are carbohydrates?
Starchy foods contain carbohydrates, which are made
of long chains of identical, small sugar molecules.
one sugar molecule
carbohydrate molecule
The body breaks down long chains of carbohydrates into
the smaller sugar molecules.
These small sugar molecules are used by the body to
release energy and make the body work.
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What are proteins?
Proteins, like carbohydrates, are made of long chains of
small molecules. In proteins, these small molecules are
not identical.
one amino acid
protein molecule
Proteins are made up of chains of small molecules called
amino acids. There are over 20 different kinds of amino acid.
Proteins are used by the body for growth and repair.
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What are fats?
Fats are made up of fat molecules, which contain fatty
acids and glycerol.
fatty acids
glycerol
fat molecule
Fat molecules have to be broken down by the body so
that they can be used for energy storage.
Fats are also used by the body to keep heat in and to
make cell membranes.
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Digestive enzymes
How do digestive enzymes help the process of digestion?
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Different types of digestive enzymes
Digestive enzymes are the chemicals that break large
insoluble food molecules into smaller soluble molecules.
Digestive enzymes are classified by the type of food that
they affect; there are three main types:
 carbohydrase – breaks
carbohydrate into smaller
sugars
 protease – breaks protein
into amino acids
 lipase – breaks fat into
fatty acids and glycerol.
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How do enzymes work?
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Carbohydrate digestion
Carbohydrates are chains of identical sugar molecules.
The digestive enzyme called carbohydrase breaks the
chemical bonds between the individual sugar molecules
in each carbohydrate chain.
carbohydrase
long carbohydrate
molecule
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sugar molecules
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Protein digestion
Proteins are made up of amino acids. There are over 20
different types of amino acids.
Proteins are digested by digestive enzymes called proteases.
These enzymes work in an acidic environment to break
proteins into smaller amino acids.
protease
long protein molecule
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amino acid molecules
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Fat digestion
Fats are digested in two stages.
Firstly, bile (released by the gall bladder) allows the fat to
‘mix’ with water by breaking the fat into smaller droplets.
This is called emulsification.
bile
Secondly, the digestive enzyme lipase breaks each fat
molecule into the smaller glycerol and fatty acid molecules.
lipase
fat molecule
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+
glycerol
fatty acids
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Which enzyme?
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The process of digestion
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Label the digestive system
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Summary
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Fitness
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What is health?
Health is a state of complete mental, physical and social
well-being, and the absence of disease or infirmity.
So a healthy person is:

physically well

mentally well

socially happy

free from disease.
What is the difference between health and fitness?
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What is fitness?
Fitness is the ability to meet the demands of the environment.
So, fitness is not necessarily about how far you can run or
how good you are at sport.
Being fit means being
physically able to cope with
the demands of everyday life.
These demands will vary
from person to person,
depending on things like
lifestyle, occupation and age.
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What is fitness?
Fitness is made up of four factors – “the four S’s”:
fitness
suppleness
stamina
strength
speed
How do these fitness factors help us in everyday life?
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Fitness factors
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Why exercise?
Regular exercise can help to keep
you healthy, by:

strengthening the heart,
reducing the risk of heart
disease

strengthening bones, reducing
the chances of osteoporosis

reducing stress, by releasing
mood-enhancing chemicals
in the brain.
Exercise also helps to maintain
and improve fitness.
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Why exercise?
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Which factor?
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Staying fit and healthy
You should aim to do a minimum
of 30 minutes of moderately
intense exercise at five times a
week (or more).
However, exercise can be
hazardous if done inappropriately.
Injuries are common from lifting
weights that are too heavy and
running on hard surfaces without
proper footwear.
How can poor exercise cause
injury to muscles and joints?
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Different types of joints
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Summary activities
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Glossary
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Anagrams
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Multiple-choice quiz
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