GCSE Year 10 A BALANCED DIET

A BALANCED DIET.AIMS:

To understand the nutritional requirements our bodies need to survive.To know what makes a healthy, balanced diet.

Starter…

True or false… Stand up if you think the following statements are true and stay sitting down if you think the statements are false

What is a balanced diet?Discuss in pairs (1 minute)

A balance diet means a diet that matches your energy needs and gives you the right amount of nutrients and fibre.

Factors Affecting Fitness • There are three reasons why we need food:

• GROWTH • ENERGY • TISSUE REPLACEMENT AND REPAIR

Q. How many components are there in a healthy diet?

7 components of a healthy diet

• There are 7 components of a healthy diet

1 minute with your partner … can you identify

all 7?

1. Carbohydrates

2. Fats

3. Protein

4. Vitamins

5. Minerals

6. Water

7. Fibre

• Stick into your book the Healthy Heptagon diagram.

• Draw an arrow from each of the sections.• Add the following information on the next

few slides to your diagram.

CARBOHYDRATE - (bread, rice, pasta)• These are broken down to glucose to provide fast-

release energy.

PROTEIN - (fish, lean meat, chicken)• Provides the fabric for most of the soft tissues. A

good protein intake is essential for growth and repair.

WATER • As most of the body is water ( 70%! ) we need to

constantly replace that which is lost in urine, sweating and breathing, by taking in fluids. This will aid in avoiding dehydration.

FIBRE - (fresh fruit and vegetables)• Fibre/roughage is indigestible plant material which

gives the gut something to push on, helping to avoid constipation. Aids water retention.

MINERALS - (greens vegetables, milk and cheese)

• Iron from the liver and green vegetables prevents thyroid problems.

• Calcium from milk and cheese produces strong teeth and bones.

• Sodium to regulate body fluids.• Iodine, used in hormone formation.

VITAMINS - ( milk, butter, citrus fruits and vegetables)

• Aid growth / Increase resistance to infection / Aids metabolism / Assist in avoiding deficiencies.

• Vitamins are chemical compounds found in the food we eat and they occur in two main groups:

• fat soluble vitamins - vitamins A, D, E and K • water soluble vitamins - vitamins B and C

• FATS - (olive oil, butter, margarine)• These contain lots of energy. Up to 70% of our

energy is supplied by fats, these can be stored for slow-release energy.

What are calories?

Calories are a measure of how much energy food or

drink contains.

How many calories does an average

female and male need per day?

An average man= 2,500

An average woman = 2,000

These values can vary depending on age and levels of physical activity, among other factors.

Pairs Work

Q. Why do sportsmen and women need to take in more calories than the average male or female. In pairs discuss and give examples from different sports. (3 mins)

Answer…• Different diets suit different sports as food

is eaten to produce energy.

• Athletes vary amounts of fats, carbohydrate and protein depending on their event…

Michael PhelpsHow many calories did he eat per

day when in full training?

12,000 calories per day…

Could you eat this amount of food?

Breakfast: Three fried egg sandwiches; cheese; tomatoes; lettuce; fried onions; mayonnaise; three chocolate-chip pancakes; five-egg omelette; three sugar-coated slices of French toast; bowl of grits; two cups of coffee• Lunch: Half-kilogram (one pound) of enriched pasta;

two large ham and cheese sandwiches with mayonnaise on white bread; energy drinks

• Dinner: Half-kilogram of pasta, with carbonara sauce; large pizza; energy drinks

Michael Phelps

Phelps, with an estimated 8% body fat, burns 1,000 calories per hour during his swimming training, compared to the equivalent exercise for an average person - vigorous walking - that would burn between 170 and 240 calories.

What sort of special diet would these guys need ?

Carbohydrate Loading• Endurance athletes will benefit from this, mainly

marathon runners.• Need to eat plenty of starch rich foods such as rice and

pasta in the week leading up to the activity.• The starch increases the amount of glycogen in the

muscles which can delay tiredness as it is a slow release form of energy.

High Protein Diets

• Often used by body builders as a means of building muscle and losing fat.

• Extra protein alone does not build muscle alone and it can be very difficult to digest.

YOUR ENERGY NEEDS.• Even when you are relaxing,

chilling out, taking part in exercise you still use up energy.

• You do this staying warm, to keep your heart beating, your lungs breathing and all the cell reactions taking place in your body.

BASAL METABOLIC RATE (BMR)

• Your basal metabolic rate (BMR) is a measure of the amount of energy you need at rest.

To move around, exercise and digest food you need extra energy known as WORKING ENERGY.

Total energy needed = BMR + working energy.

This is measured in kilojoules (kJ) or kilocalories (c)1C = 4.18kJ

Q. What do you think your energy

needs depend on?(discuss in pairs 2 minutes)

ENERGY NEEDS FOR DIFFERENT PEOPLE.

• Your age: you need more as a teenager than when you do when you are 40 because your metabolism slows down.

• Your gender: males generally need more energy.

• Your lifestyle: the more active you are the more energy you require.

- Frequency, type and intensity of exercise- body composition- Fuels available

THE ENERGY BALANCEJust for information

• If you need 10,000kJ a day and you eat enough food for 15,000kJ. The extra food is not excreted, it is stored as fat.

• If you continue eating more than you require, you get fat or obese.

• If you do not eat enough food than you require you can become anorexic.

Energy intake and expenditure

Therefore food intake needs to take into account

BMR PLUS additional energy expenditure due to

exercise.

Energy intake and expenditure

Metabolic rates vary between individuals and it gets slower as

you get older. True or false?

TRUE

Energy Balance

Exam questions.

• Explain why a teenager needs more energy than a retired female [3].

• What two units are used to measure energy? [2].

• If you eat more food than you need for energy, what happens to the extra? [2].

• What is a balanced diet? [2].