Nutrition

Natural sciences

Grade 9

Life processes: healthy life

Module 1

Nutrition

Nutrition

People are heterotrophic organisms and therefore have to take in food by eating plants or animals to obtain energy for growth and recovery.

Food has to be digested to release nutrients and provide energy.

Energy is required for all activity and life processes.

The human diet comprises all the food and liquids that are taken in.

The study of all aspects involving diet is called nutrition .

Food is divided into the following main groups:

• Dieticians use a different classification with recommended daily allowances (RDA). They recommend that you eat a particular number of portions (shown in brackets) of dairy products (2), grains (2-4), proteins (2-3) and fruit and vegetables (3-5) each day.

Activity: energy per day:

• Study the values in the columns and answer the questions that follow:

INDIVIDUAL

kJ per day

1. Why do you think men and women have different kJ requirements?

2. Why do pregnant and lactating women have such a large kJ requirement?

3. Why does a mineworker have such a large kJ requirement?

4. What does kJ stand for?

5. Explain the reduction in the energy requirements of older women.

YOUR FOOD INTAKE

• Complete the following table dealing with your food intake for the past 24 hours. Indicate the food groups by using the codes: Protein (P), Carbohydrates (C), Fats (F).

1. How many portions of protein have you eaten?

2. How many portions of fruit and vegetables have you eaten?

3. How much water did you drink?

4. Have you followed a balanced diet? If not, explain how you ought to adjust your diet.

5. Draw a pie chart to show the proportion of carbohydrates , proteins and fats that you have eaten over the 24-hour period.

Activity: DEMONSTRATION: FOOD TESTS

• complete the following after the demonstration:

Assessment

Learning Outcomes 1 : Scientific Investigation

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

We know this when the learner:

• conducts investigations and collects data;
• evaluates data and communicates findings.

Learning Outcomes 2 : Constructing Science knowledge

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

We know this when the learner:

• interprets information.

Memorandum

ACTIVITY: Energy values and graph:

1. Men are more active.

2. A woman’s body has to process extra nutrients and operate more processes.

3. Very active.

4. kilojoules – A joule is the unit of work or energy.

5. They have a slower metabolism – are less active.

ACTIVITY: ANALYSING YOUR FOOD INTAKE

Own observations

CLASS ACTIVITY: Food test demonstration

• Test for starch: brown iodine solution. Becomes purplish-black.
• Grease-spot test: translucent greasy spot on paper.