1. 3.2.3.3 - Energy use, diet, nutrition and hydration
Learning objectives
To understand the role and importance of macronutrients and micronutrients.
To describe how the body gets energy from nutrients and the role of these within the body.
To explain the importance of hydration for physical activity.

2. Energy use
Photo by: © paddynapper on Flickr. This image is reproduced under the terms of the Creative Commons License 2.0.
Watch me
How does the nutritional requirements change for different athletes?

3. Energy use
Energy is measured in calories (Kcal) and is provided through the food we eat. The average male requires 2500 Kcal per day and females 2000.
Photo (footballer): © LOCOG
Photo (runner): © bleublogger on Flickr. This image is reproduced under the terms of the Creative Commons License 2.0.
Think. Pair. Share – For what reasons might the average calorie intake change?

4. Energy use
The following factors can alter the number of calories required by an individual.
Height
Gender
Energy expenditure (exercise)
Age
Some athletes need to maintain their weight carefully and as such will pay close attention to their dietary intake.
i.e. boxers and jockeys
Photo by: ©

5. Energy, diet and hydration
The energy requirements for physical activity can differ dependant on many factors.
Exercise/intensity level - The higher the exercise intensity the more energy needed.
Age – Younger individuals need more energy than older adults.
Gender – Women tend to need less energy intake than men.
Photo by: © LOCOG

6. Energy, diet and hydration
A balanced diet is essential for health as well as to cope with the physical demands of sport.
A balanced diet is needed as:
Unused energy is stored as fat which can cause obesity.
Energy stores are ready for exercise.
Nutrients are needed for energy, growth and hydration.
Photo: ©
Think. Pair. Share – What should be included in a balanced diet?

7. Nutrition
A balanced diet involves consuming each element in proportion.
Photo: ©

8. Nutrition
1. Carbohydrates – this macronutrient is the ‘fuel’ that provide us with energy to sustain performance.
Photo: © Stock.xchng.
Glucose in the form of Glycogen is broken down from carbohydrate to provide energy.

9. Nutrition Other sources of carbohydrate: Fruit Bread Rice Pasta
Potatoes

10. The fitter you are the more easily your body uses up stores of fat
Nutrition
2. Fats – These are also used for energy, but only when stores of carbohydrate run low. Fat provides very slowly released energy. This is important for endurance activities. The longer you work the more fat is used.
The fitter you are the more easily your body uses up stores of fat
Photo: © bleublogger on Flickr. This image is reproduced under the terms of the Creative Commons License 2.0.

11. Nutrition
Other sources of fats:
Butter
Cheese
Fried and snack foods

12. Nutrition
3. Protein – Protein is an essential nutrient that promotes growth and repair of muscles.
Proteins are also used to generate energy only when the body has exhausted its stores of carbohydrates and fats.
Proteins are especially important for sportspeople who need to build up large, powerful muscles.
Performers in sports like weightlifting, rugby and sprinting need a high protein diets.
Photo: © LOCOG

13. Nutrition
Other sources of protein:
Eggs
Chicken
Fish

14. Nutrition
Proteins are also needed by performers who are recovering from injury in order to repair damaged tissue.
Photo: © Stock.xchng.

15. Nutrition
4. Minerals – Your body needs minerals to help it function. In particular minerals increase the efficiency of carrying oxygen to muscles.
Minerals can be found in:
Calcium in milk
Iron in meat
Minerals are only needed in small quantities but are vital for the body.
Photo: © Stock.xchng.
Photo: © Stock.xchng.

16. Nutrition
5. Vitamins – these generally contribute to the general health of an athlete.
Photo: © Stock.xchng.
Vitamins are needed to:
Resisting infection and disease
Regulate chemical reactions in the body.

17. Water balance - hydration
Photo: © Stock.xchng.
Watch me
What are the effects of dehydration on athletes?

18. Water balance - hydration
It is essential to keep taking a small amount of fluid at regular intervals during exercises to enable the body to function properly.
Symptoms of dehydration are tiredness, lack of concentration and headaches.
Photo: © Stock.xchng.
Photo: © deshow.net
Performers exercising in hot climates may need to drink up to 2 litres of water per hour!

19. Water balance - hydration
Dehydration in the body can cause:
Blood thickening which slows blood flow around the body.
Increased heart rate/irregular heart rhythm.
Increased body temperature.
Slower reaction time/poor decision making.
Increased muscle cramps and fatigue.
Photos: © Stock.xchng.

20. Apply it! Energy, diet and hydration What has stuck with you?
Name the 3 elements of a balanced diet?
How will the diet of a sprinter differ to that of a marathon runner?
Why is water vital part of a balanced diet?
What factors will cause an athlete to consume more calories than the recommended daily intake?
Energy, diet and hydration

21. Practice it! Exam questions
1. Sports performers make sure they eat a balanced diet.
Briefly explain the importance of carbohydrates and protein to an elite sports performer.
(i) Carbohydrates (2)
(ii) Protein (2)

22. Practice it! Exam questions
2. Summarise the effects of dehydration on the body. (3)
Photo: © istock photo

23. Practice it! Exam questions
3. A group of amateur runners are attempting their first marathon.
Some of the runners take advantage of the drinks offered to them
during the race whilst others do not.
Evaluate the actions of the runners who do not take advantage of
the drinks available (3)
Photo: © istock photo

24. Practice it! Marks Scheme:
(i) A linked explanation, e.g. Carbohydrates provide energy (1) so quality of performance remains high/optimum performance (1) Carbohydrates provide energy (1) so they can last longer in their game/race/event. Carbohydrates provide energy (1) so they can maintain/continue activity level in game/race/event without tiring.
(ii) Protein is used for growth/ increased muscle mass/bigger muscles (1) so stronger/powerful/faster for their event (1) Repair of tissue/muscle (1) to recover from injury/quicker recovery (1)
2. Increased heart rate (beats per minute), increased lactate acid in muscles (increased blood acidity), increased body temperature, decreased strength.

25. Practice it! Marks Scheme: 3.
More likely to suffer from dehydration, which has a negative effect on running performance (1)
More likely to suffer from increases in heart rate so the heart has to work harder to supply oxygen to the muscles when running (1)
Reduction in blood flow to working muscles / thicker (viscous blood) which means less oxygen to the muscles and it is harder to remove waste products – slows recovery so harder to continue in the marathon (1)
Increase in body temperature so body could overheat during the race and become faint / pass out and cannot carry on (1)
Muscle fatigue more likely which could cause cramps so cannot carry on (1)