Transcript a powerpoint presentation on Yr 10 A Healthy Diet

A balanced, healthy diet?
A Healthy Diet
Is an important part
Of an active, healthy
lifestyle
Growth
Energy
Tissue replacement
and repair
A balanced diet provides us with all the nutrients we need,
but not too much of things such as salt, sugars or fats
which could lead to ill health.
Carbohydrates
Water
Protein
7
Essential
components
Fibre
Fats
Vitamins
Minerals
Carbohydrates
• Are made up of the
chemical elements of
carbon, hydrogen and
oxygen.
• They are high in glucose
and are primarily involved
in energy production.
• Stored in the body
(muscles, liver and
kidneys) as glycogen in
limited but readily
available amounts which
need to be replenished
Complex
or
carbs?
Release energy slowly over a long
period of time
simple
Include glucose and fructose and
provide a quick energy fix
Carbohydrates
• Are essential to the nervous system and determine fat
metabolism.
• Are very important to the athlete, especially in high
intensity exercise, (about 60% of an athletes diet should
be carbohydrate).
• When exercise takes place, glycogen is broken down to
glucose which supplies muscles with energy.
• When glycogen stores are depleted, there is less energy
available and the performer will become tired.
• Carbo loading.
Daily calorie intake
• The UK Dept of Health EAR (estimated
average requirement) is 1,940 calories per
day for women and 2,550 for men (313
grams of carbohydrate).
• Leading up to Beijing Michael Phelps was
reported to be eating about 12,000
calories a day.
Fats
• Supplies approx 70%
of our energy
requirements
• Is the body’s
preferred energy
source
• A major source of
energy for athletes
performing lowintensity endurance
exercise
Fats
• Fats (or lipids) are made up of carbon,
hydrogen and oxygen, but in different
proportions to carbohydrates.
• Two types:
triglycerides – stored in the form of body
fat
fatty acids – used mainly as fuel for energy
production (can be either saturated or
unsaturated)
Saturated fats
• Solid form at room
temperature (eg lard)
• Primarily from animal
sources
• Meat products, dairy
products, cakes,
confectionery
Unsaturated fats
• Liquid form eg in
vegetable (olive) oil
• Mainly from plant
sources eg nuts
• Also from oily fish
Fats
• When muscle cells are readily supplied with oxygen, fat
is the usual and preferred fuel for energy production
• This is because the body is trying to save the limited
stores of glycogen for high-intensity exercise and
therefore delays the onset of fatigue
• But the body cannot solely use fat for energy and so the
muscles are fuelled by a combination of fat and glycogen
• Fat is also very important to protect vital organs and is
crucial for cell production and the control of heat loss.
Fats
• Fat consumption
should be carefully
monitored and can
cause obesity
• It is generally
accepted that a
maximum of 3% of
total calories
consumed should be
from fatty foods
Protein
Meat, fish and poultry – complete
proteins
Vegetables, nuts and grains –
incomplete proteins (lacking in
essential amino acids
Protein
• Composed of carbon,
hydrogen, oxygen and nitrogen
and some contain minerals
such as zinc.
• Proteins are a potential source
of energy, but are not used if
fats and carbohydrates are in
plentiful supply.
• Important for repair and growth
of new tissue.
• Also important in development
of hormones, enzymes and
haemoglobin in the blood.
• Should account for approx.
15% of total calorie intake.
Protein
• Excessive protein intake can
lead to kidney damage.
• Protein breaks down more
readily during and after
exercise.
• The amount of protein broken
down depends on how long
and how hard you exercise.
• Increased protein intake may
be important during the early
stages of training to support
increases in muscle mass and
myoglobin
Minerals
• Are non-caloric and are
inorganic elements
essential for our health,
e.g. building tissue
• Minerals can be lost
through sweating –
implications for exercise –
minerals should be
replaced quickly to
ensure good health
Macro minerals
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E.g. calcium, potassium and
sodium (regulates body fluids)
These are needed in relatively
large amounts (although beware
too much salt, which can
contribute to high blood pressure,
heart and kidney disease)
Calcium is essential for healthy
bones and teeth. A deficiency
increases the likelihood of
osteoporosis and bone fractures
Calcium is found in milk and dairy
products, green vegetables and
nuts. It needs vitamin D (found in
sunlight) to be absorbed.
Trace elements
• E.g. iron, zinc and manganese.
• These are needed in small
amounts.
• Iron is an essential component
of haemoglobin which carries
O2 in the blood.
• Iron deficiency anaemia can
impair performance in
endurance events. However,
too much can be dangerous.
• Iron can be found in meat
(especially red meat and offal),
fish, dairy produce and
vegetables.
Vitamins
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Non caloric chemical compounds
needed by the body in small
quantities.
Fat soluble (A,D,E)
Water soluble (B,C)
Vital in the production of energy,
the functioning of our metabolism
and the prevention of disease.
Vitamins found in fresh fruit and
vegetables.
Extremely large doses can be
dangerous
Little evidence to support
supplementary vitamin pills
enhancing performance
Most excess vitamins are excreted
via urine
Fibre
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No calories, vitamins or minerals in
fibre and not digested when we eat it.
2 types, soluble and insoluble, found in
the cell walls of plants (found in
wholegrains, fruit & veg)
Essential for healthy bowel function
Helps to retain water (thus increases
the bulk of waste matter, makes it
softer and increases speed and ease
with which it passes through the
bowel).
Reduces risk of constipation,
haemorrhoids and cancer of the colon
or large bowel
Deficient in many peoples diets. Aim
for an intake of around 18gm a day.
Water
• Essential for good health.
• Makes up more than 70% of
the body
• Carries nutrients and helps
remove unabsorbed food &
waste products
• Essential for body’s chemical
reactions
• Essential part of blood
• Esssential in temperature
regulation (sweat & urine)
• Should drink approx 2 litres a
day.
Dehydration and sport
• Important to take fluids
during prolonged
exercise.
• Dehydrated individuals
become intolerant to
exercise and heat stress
• The CV system becomes
inefficient
• Inability to provide
adequate blood flow to
the skin > heat
exhaustion
Composition of a healthy diet
Carbohydrate – 50%
Fat – 30-35%
Protein – 15-20%
The National Institute for Health and Clinical
Excellence (NICE) recommends:
• Base your meals on starchy foods such as potatoes,
bread, rice (wholegrain where possible) and pasta.
• Eat plenty of fibre rich foods such as oats, beans, peas,
lentils, grains, seeds, fruit and vegetables.
• Eat at least 5 portions of a variety of fruit and vegetables
a day in place of foods high in fat and calories.
• Avoid foods containing a lot of fat, sugar and salt such
as fried food, (‘takeaway foods’), sweetened drinks,
sweets and chocolate.
• Eat breakfast
• Regulate portion sizes
• Avoid too much alcohol
Alcohol
• Is a concentrated source of energy but is not
available during exercise for our working
muscles
• The Health Development Agency and NICE
recommend no more than: 3-4 units per day for
males, 2-3 units per day for females
• Avoid ‘binge drinking’. Spread your alcohol
consumption and leave some alcohol free days
• One unit = half pint of beer (30 calories),
standard glass of wine(90 calories), single
measure spirits (50 calories)
Basic considerations
• Food is meant to be enjoyed
• You don’t have to give up all of your
unhealthy ‘bad’ foods
• The right balance is essential for health
and fitness
Other factors to keep in mind which
affect food choices
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Culture, morals, ethics
Family influences
Peer group influences
Lifestyle
finance