IGCSE · Practice questions · Diet

All seven, in proportion.

Six original Cambridge-style questions on a balanced diet, the sources and importance of each nutrient, deficiency diseases and interpreting food data.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Source, job, deficiency.

Balanced diet: all the nutrients in the correct proportions and amounts.
Energy: carbohydrates and fats; growth and repair: proteins.
Scurvy = lack of vitamin C; rickets = lack of vitamin D or calcium.
Fibre is not digested: it adds bulk for peristalsis and prevents constipation.

Recall

[2 marks]

Describe what is meant by a balanced diet.

A diet containing all the nutrients: carbohydrates, fats and oils, proteins, vitamins, mineral ions, fibre and water. ✓
In the correct proportions and amounts to meet the body's needs (including enough, but not too much, energy). ✓

Recall

[4 marks]

For each of the following, name one good dietary source and state why the body needs it: (a) protein, (b) iron, (c) calcium, (d) carbohydrate.

(a) Protein: meat, fish, eggs or beans; for growth and repair of cells (making enzymes and antibodies). ✓
(b) Iron: red meat, liver or beans; to make haemoglobin in red blood cells. ✓
(c) Calcium: milk or cheese; for strong bones and teeth (and blood clotting). ✓
(d) Carbohydrate: rice, bread or potatoes; as the main source of energy for respiration. ✓

Calculation

[3 marks]

A teenager needs about 1000 mg of calcium a day. A glass of milk contains 300 mg and a portion of cheese contains 240 mg. (a) Calculate the percentage of the daily need supplied by one glass of milk and two portions of cheese. (b) State how much more calcium is needed to reach 100%.

(a) Total = 300 + (2 × 240) = 780 mg. ✓
Percentage = 780 ÷ 1000 × 100 = 78%. ✓
(b) 1000 − 780 = 220 mg more is needed. ✓

Explain

[3 marks]

Explain why a person whose diet lacks vitamin D may develop rickets even though they drink plenty of milk.

Milk provides calcium, which is needed for strong bones. ✓
Vitamin D is needed for the body to absorb calcium from the food. ✓
Without vitamin D little calcium is absorbed, so the bones are soft and weak and bend: rickets. ✓

Explain

[3 marks]

Fibre is not digested by humans. Explain why it is still an important part of the diet.

Fibre adds bulk to the food in the intestines. ✓
The muscles of the gut wall can push bulky food along more easily (peristalsis). ✓
This prevents constipation (food and faeces move through at a steady rate). ✓

Data

[4 marks]

The table shows the nutrients in 100 g of three foods.

Food	Protein / g	Fat / g	Vitamin C / mg	Fibre / g
A	25	12	0	0
B	3	0.3	80	3
C	8	0.5	0	7

(a) Suggest which food is oily fish, which is broccoli and which is beans. (b) Which food would best help to prevent scurvy? Give a reason. (c) A diet made only of food A would not be balanced. Give two reasons.

(a) A = oily fish (high protein and fat), B = broccoli (high vitamin C), C = beans (protein and high fibre). ✓
(b) B, because it contains the most vitamin C, and a lack of vitamin C causes scurvy. ✓
(c) It contains no vitamin C, so scurvy could develop. ✓
It contains no fibre (and little carbohydrate), so constipation is likely and too much energy would come from fat. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.