Nutrition
Physical Education: AQA GCSE, topic 8.3.1
Energy Use
Energy is measured in kilocalories (kcal) or calories (cal). These calories are taken in from the foods that we eat. People need different amounts of calories based on:
Gender
- On average, males consume 2,500kcal per day and females consume 2,000kcal per day.
Age
- Once a person is over the age of 25, their calorie needs begin to fall as their metabolism (chemical processes in the body that keep us alive) slows down.
Height
- A taller person needs more calories because they have more body tissue to provide energy for.
Energy expenditure
- This depends on how much exercise an individual does each day. A more active person needs more energy than someone who is less active.
- Elite athletes often need more than 2,000 or 2,500kcal per day.
Basal metabolic rate (BMR)
- This is how fast energy is being used by the individual's body.
Nutrition
We are not able to get all of the nutrients we need from 1 item of food. We need to eat a variety of foods to have a balanced and healthy diet.
Balanced diet
- A balanced diet is one that contains different types of foods that give us all of the nutrients we need to stay healthy.
- It is important to make sure that we do not have too much of any particular nutrient because this is also unhealthy.
Reasons for balanced diet
- Unused energy is stored as fat in the body. This could lead to obesity, which is linked with serious health problems.
- We need to consume suitable amounts of calories to exercise and carry out any other physical activity.
- The body needs a variety of nutrients to have the energy to move, grow repair tissue, and stay hydrated.
The 7 key nutrients
- Carbohydrates.
- Fat.
- Protein.
- Fibre.
- Vitamins.
- Minerals.
- Water.
Proportions of carbohydrates, fats and proteins
- The following percentages are recommended for carbohydrates, fats and proteins:
- Carbohydrates = 55-60% of a person's diet.
- Fat = 25-30% of a person's diet.
- Protein = 15-20% of a person's diet.
Test yourself on Nutrition
Which unit is a measure of energy?
Who would typically need more calories?
What does BMR stand for?
How many key nutrients are there?
Reasons to have a balanced diet