Resource 5: Data on food and energy
Teacher resource for planning or adapting to use with pupils
A healthy diet requires adequate amounts of protein, carbohydrate, fat, vitamins, minerals and water.
A rough guide to daily requirements is as follows:
- protein 50 g
- carbohydrate 300 g
- fat 65 g
- fibre 30 g
- vitamin A 730 μg
- vitamin C 60 mg
- iron 11 mg (males), 15 mg (females)
- calcium 1300 mg.
Note the different units for different nutrients:
1 mg = 1/1000 g 1 μg = 1/1000 mg.
Sources of the main nutrients
|Food||Rich source of||Moderate source of|
|Cereals||Starch, fibre||Protein, B vitamins, many minerals|
|Starchy roots and fruits (yams, maize, cassava, potatoes, rice)||Starch, fibre||Some minerals, vitamin C if fresh, vitamin A if yellow or orange|
|Beans and peas||Protein, starch, some minerals, fibre||B vitamins|
|Oilseeds||Fat, protein, fibre||B vitamins, some minerals|
|Fats and oils||Fat||Vitamin A if orange or red|
|Dark to medium-green leaves||Vitamins A and C, folate||Protein, minerals|
|Orange vegetables||Vitamins A and C||Fibre|
|Orange fruits||Vitamins A and C||Fibre|
|Citrus fruits||Vitamin C||Fibre|
|Milk||Fat, protein, calcium, vitamins|
|Eggs||Protein, vitamins||Fat, minerals (not iron)|
|Meat||Protein, fat, iron|
|Liver||Protein, iron, vitamins|
Sources of vitamins
|Vitamin A||Liver, fish liver oils, egg yolk, milk and dairy products, green leafy vegetables (especially kale, amaranth, sweet potato, cowpea and cassava leaves), yellow and orange-coloured fruits and vegetables (carrots, pumpkin, mango, papaya, oranges), orange-coloured sweet potato, palm oil|
|Vitamin D||Cod-liver oil, oily fish, liver, egg yolk|
|Vitamin E||Vegetable oils (such as maize, soybean and sunflower oils), nuts, soybeans, cereals, egg yolk|
|Vitamin K||Green leafy vegetables, vegetable oils, egg yolk, beef, mutton, poultry|
|Thiamine (vitamin B1)||Millets, sorghum, wheat, maize, dried beans, rice, liver, kidney, beet, nuts|
|Riboflavin (vitamin B2)||Green leafy vegetables, liver, kidney, milk, cheese, eggs, whole grains|
|Niacin (nicotinic acid and nicotinamide)||Lean meat, poultry, fish, groundnuts, dried beans, wheat, yam, potato|
|Pantothenic acid||Kidney, fish, egg yolk, most vegetables, most cereals|
|Pyridoxine (vitamin B6)||Meat, poultry, fish, egg yolk, whole grains, banana, potato, dried beans, lentils, chickpeas|
|Biotin (vitamin H)||Groundnuts, dried beans, egg yolk, mushrooms, banana, grapefruit, watermelon|
|Folic acid||Green leafy vegetables (losses from cooking can be high), fresh fruits (especially orange juice), dried beans, peas, nuts, egg yolk, mushrooms, banana, liver|
|Vitamin B12 (cyanocobalamin)||Liver, kidney, chicken, beef, fish, eggs, milk, cheese|
Extension activities: food and energy
We need energy to stay alive and carry out our daily activities. This energy comes from the food we eat. Energy is measured in units called joules (J). One joule is quite a small amount of energy, so we usually use kilojoules (kJ) to measure our energy requirements.
- 1 kilojoule = 1000 joules.
Teenagers should eat enough food to provide them with between 10 000 and 15 000 kJ each day. The exact amount required will vary according to size (mass), age, sex (in general boys need more than girls) and activity.
On average, a teenage girl needs 11 000 kJ of energy each day.
On average, a teenage boy needs 13 000 kJ of energy each day.
Plan a diet for a day for a teenage boy or girl. The food you select and the amounts of each food should be enough to meet the energy requirements of an average teenager as given above. Do not forget to include snacks as well as main meals.
Use the information in the table below to help you. You will need to estimate how many grams of each food you will require before you calculate the energy it provides.
Energy content of some common foods
|Food||Energy content in kJ per 100g||Food||Energy content in kJ per 100g|
|Haricot beans||1073||Biscuits (sweet, rich)||2078|
|Broad beans||289||Bread (brown)||993|
You can record your diet plan in a table like the one below.
Energy content of a sample diet for a teenager for one day
|Meal||Food item||Amount of this food in g||Energy content of this food in kJ per 100g||Total energy provided by this food item in your diet|
- Calculate the overall total energy in kJ that your diet will provide.
- How does this compare with the average requirements for a teenager of your sex?
Diet, energy and activity
Your energy requirements will vary according to your activities. The table below shows the energy requirements for different activities.
Energy requirements for different activities
|Activity||Energy required for each minute by an average teenager in kJ||Activity||Energy required for each minute by an average teenager in kJ|
|Watching TV||5||Digging the garden||24|
|Washing clothes||10||Playing football||36|
Plan a day where you do various activities for a certain length of time.
A day lasts 24 hours or 1440 minutes.
Activities (and their durations) you might choose could be sleeping, 480 minutes; eating, 50 minutes; swimming, 70 minutes and so on.
Work out how many kilojoules of energy you would need for each activity.
You could record your answer in a table like the one below.
Activities in a day and energy required to perform them
|Activity||Minutes||Energy required per minute for this activity in kJ||Total energy required for the duration of this activity|
- Calculate the overall total energy in kJ that your activity plan would require.
- How does this compare with the amount of energy your diet in Task 1 would provide?