A balanced diet, and what each nutrient is for

What this chapter is for

Four Pakistani children in ten were too short for their age in 2018, and the reason was not only how much they ate but what they ate. This chapter teaches what the body needs from food, what each nutrient does inside you and what happens when one is missing, then puts it together as a plate of ordinary Pakistani food and as the country’s own nutrition figures.

It is a long chapter, so here is its shape. The first four sections explain what a balanced diet is and how food energy is counted. Fourteen take the nutrients one at a time, carbohydrate, fat, protein, the vitamins, the minerals, fibre and water. Four put them on a plate, from the gut that takes food apart to a cheap balanced day. The last four take malnutrition, body weight and where Pakistan stands.

FPSC prints this line under Food Science as “Concept of Balance Diet :- Vitamins, Carbohydrates, Protein, Fats and oil, Minerals, Fiber.”¹ Eleven part-questions in the papers from CE-2016 to CE-2025 have come from this chapter’s ground, from a question on cholesterol and a note on balanced diet to the digestion of carbohydrates and the food groups.²

Before you start

The words you need

The story in plain words

1. The body needs energy to work, material to build itself, and small amounts of certain chemicals to keep its machinery running.
2. Energy comes mainly from carbohydrate and fat. Building material comes mainly from protein.
3. The small chemicals are the vitamins and minerals, and food must supply most of them.
4. A balanced diet gives all of these in the right amounts, from food a person can get and eat.
5. If one is missing for long enough, a named disease follows, such as night blindness without vitamin A or goitre without iodine.
6. If energy and protein are both short, a child stops growing. That is Pakistan’s most serious nutrition problem.
7. Too much of the wrong food is malnutrition too, and it brings obesity, diabetes and heart disease.
8. Pakistan has both problems at once, and the cheapest answers are roti with daal, vegetables, milk, clean water, iodised salt and fortified flour.

1. What a balanced diet is

A man who eats three kilograms of boiled rice a day is not hungry, yet he is badly fed. Rice gives him plenty of energy but little protein, no vitamin A and very little iron, so after some months his body starts to show what is missing. That is the idea behind a balanced diet. It is about the right mix, not only about filling the stomach.

A balanced diet is one that supplies all the nutrients the body needs, in the amounts it needs them, from foods a person can get and digest. Learn that sentence, because it is the definition an examiner can mark. WHO describes a healthy diet with four principles that fit inside it.³ Adequacy means meeting the body’s needs without going over them. Balance means energy eaten matches energy spent, with a sensible split between carbohydrate, fat and protein. Moderation means limiting what harms, such as salt, sugar and unhealthy fat, and diversity means eating many different foods from every food group.

Three points sit under the definition. The balance is judged over the whole day, not in each dish, so a breakfast of paratha need not be balanced if the rest of the day makes up for it. The balance also depends on the person. A labourer digging a canal, a pregnant woman and a two-year-old need different amounts of the same nutrients, so a diet balanced for one may not suit another.

The last point is that a diet must be safe as well as balanced. WHO adds that a healthy diet is free from germs and harmful chemicals, and it warns that people now eat more highly processed food and less fruit, vegetables and fibre than they should.³ A plate of perfectly mixed food cooked in dirty water still makes a child ill, which is why this chapter comes back to water and sanitation more than once.

2. The six nutrients and the three jobs of food

There are six classes of nutrient. Carbohydrate gives energy. Fat gives concentrated energy and carries some vitamins into the body. Protein builds and repairs the body, the vitamins and minerals keep its machinery working, and water is the medium in which everything happens. Water carries no energy at all, but it counts as a nutrient because the body cannot work for long without it.

Many writers add fibre as a seventh, the part of plant food the gut cannot digest. FPSC’s own syllabus line names fibre separately from the rest, so an answer on balanced diet should name it separately too.¹ WHO counts about thirty micronutrients in all, thirteen vitamins and sixteen minerals, needed in small amounts for growth and health.³

A list of six words does not yet show what to eat, so teachers of nutrition have long sorted foods by the main job they do. Energy-giving foods are cereals, rice, potato, sugar, oil and ghee, and in Pakistan the wheat roti does most of this work. Body-building foods are milk, eggs, meat, fish, pulses and nuts, which carry the protein. Protective foods are vegetables, fruit and milk, which carry the vitamins and minerals that protect the body from deficiency disease.¹⁰

The three-way split still earns marks because it turns a list of nutrients into food on a plate. Milk sits in two columns, since it carries protein and calcium both. Use the split as the backbone of a short answer, then add the six nutrients and what each does.

3. Energy, and how it is counted

Food energy is counted in kilocalories, written kcal. One kilocalorie is the heat needed to warm one litre of water by one degree Celsius, and the scientific unit, the kilojoule, is a little smaller, since one kilocalorie equals 4.184 kilojoules.¹⁰ When a biscuit packet says 150 calories, it means 150 kilocalories.

Three numbers do most of the work. One gram of carbohydrate gives about 4 kcal, one gram of protein about 4 kcal, and one gram of fat about 9 kcal.¹⁰ Fat carries more than twice the energy of the same weight of carbohydrate. That one fact explains why a spoon of oil makes a child’s food richer without making it bulkier, and also why too much oil and ghee puts on weight so quickly.

Here is how to use the numbers. Suppose a meal holds 60 grams of carbohydrate, 15 grams of protein and 10 grams of fat. The carbohydrate gives 60 × 4 = 240 kcal, the protein gives 15 × 4 = 60 kcal, and the fat gives 10 × 9 = 90 kcal. The meal holds 240 + 60 + 90 = 390 kcal, and fat supplies 90 of those 390, about 23 per cent.

Now try one with the same steps beside you. A plate of fried snacks holds 50 grams of carbohydrate, 10 grams of protein and 20 grams of fat. Work out its energy and the share that comes from fat before you open the answer.

4. Where the energy goes, and how a day should be split

Most of a day’s energy goes on doing nothing at all. The basal metabolic rate is the energy the body spends lying completely still, to breathe, keep the heart beating, keep warm and run the brain, liver and kidneys, and for most adults it is the largest single part of the day’s use.¹⁰ Physical activity comes next, and it is the part that differs most. A clerk and a mason working the same hours spend very different amounts, and a person doing very heavy work in a cold climate may need as much as 4,000 kcal a day.¹⁰ Growth, pregnancy and breastfeeding add more on top.

Energy in and energy out have to match. Eat more than you spend and the extra is stored as fat. Eat less and the body burns its own fat, then its own muscle. Both directions are malnutrition, and WHO’s definition includes overweight and obesity beside undernutrition.⁴ An answer that treats malnutrition as hunger alone has thrown away half the question.

WHO also says how the day’s energy should be split between the three energy nutrients.³ Carbohydrate should give about 45 to 75 per cent, mostly from whole grains, vegetables, fruit and pulses. Fat should give at least 15 per cent and, for adults, no more than about 30 per cent. Protein at 10 to 15 per cent is enough for most adults, which is about 50 to 75 grams for a person eating 2,000 kcal.

Pakistan’s own dietary guidelines put carbohydrate at 45 to 65 per cent of energy, a slightly narrower band than WHO’s.¹³ Either way the base of the day is the starchy staple, which in Pakistan means wheat.

5. Carbohydrates and their three classes

Carbohydrates are compounds of carbon, hydrogen and oxygen. The body burns them for energy and gives out carbon dioxide and water, and they are the cheapest source of energy there is, which is why they form the base of every poor country’s diet.¹⁰ All carbohydrates are built from sugar units, each a ring of atoms, and the way to classify them is to count the rings.

Monosaccharides are single sugar units. They need no digestion and pass straight through the wall of the gut. Glucose is the one the body runs on, and most other carbohydrates are turned into it before they are used. It is found in fruit, sweet potato and onion. Fructose is the sugar of honey and many fruits, and galactose comes from the breakdown of milk sugar.¹⁰

Disaccharides are two sugar units joined, and they must be split into single units before the body can absorb them. Sucrose is ordinary table sugar from cane or beet, and it is also in carrots and pineapple. Lactose is the sugar of milk and is much less sweet. Maltose is found in sprouting grain.¹⁰

Polysaccharides are long chains of many sugar units, mostly insoluble in water. Starch is the great energy food of cereals, potato and cassava, and cooking bursts its grains, which is why cooked starch is easier to digest. Glycogen is the small store the body makes from extra sugar and keeps in the liver and muscles. Cellulose, together with hemicellulose, pectin and gums, cannot be digested by people at all, so these are called unavailable carbohydrates, and they make up most of dietary fibre.¹⁰

That is the classification FPSC asked for in CE-2020, “What are carbohydrates? Classify and give detail of each class along with examples.”² Give the three classes, say what each is in one line, and name three examples of each.

6. Sugar, and how much is too much

Free sugars are the sugars a factory, a cook or you add to food, together with the sugar in honey, syrup and fruit juice. The sugar inside a whole fruit is not counted, because it comes wrapped in fibre. WHO’s advice is to keep free sugars under 10 per cent of a day’s energy, which for an adult eating 2,000 kcal is 50 grams, about 12 level teaspoons, and it says going below 5 per cent may bring more benefit.³ WHO also says the cut should not be made by switching to sweeteners such as aspartame, saccharin or stevia.³

Pakistani households bought 1.22 kilograms of sugar per person per month in 2024-25.⁸ Spread over the month, that is about 40 grams a day, close to 10 teaspoons, and it counts only sugar bought as sugar. The sugar in biscuits, sweets, bakery items and soft drinks comes on top.

The trouble with free sugar is that it brings energy with nothing else. A glass of cola gives the energy of a roti but none of its protein, B vitamins or fibre, so a diet heavy in sugar can be too rich in energy and short of everything else at once. It also feeds the bacteria that cause tooth decay.

7. Fats, and why the body needs them

Fat is an essential nutrient, and an answer should say so plainly. Every cell needs it, and two fatty acids, linoleic acid and alpha-linolenic acid, cannot be made by the body at all, so they must come from food.³ They are called essential fatty acids for that reason. Fat also carries the fat-soluble vitamins, A, D, E and K, into the body, so a meal of greens with no oil at all delivers far less vitamin A than the same greens cooked with a spoon of oil.¹⁰

That is why WHO sets a floor as well as a ceiling. Adults should get at least 15 per cent of their energy from fat, and limiting total fat to about 30 per cent helps prevent unhealthy weight gain.³ Children may need a higher share, because they have to grow on a small stomach, and fat packs the most energy into the least food.³

The body stores spare energy as fat under the skin and around the organs. A store carries a person through a lean season, which mattered for most of human history. Today the danger in Pakistan’s towns runs the other way, with too much stored fat and the diseases it brings.

8. Saturated, unsaturated and trans fat

Fats are made of fatty acids, which are long chains of carbon atoms. In a saturated fatty acid every carbon carries as many hydrogen atoms as it can hold, so the chain is straight. Straight chains pack tightly against one another, which is why fats rich in them, such as butter, ghee, fatty meat and lard, are solid at room temperature. Coconut oil and palm oil are the plant fats that are largely saturated.¹⁰³

An unsaturated fatty acid has one or more double bonds where hydrogen is missing, and at each one the chain bends. Bent chains cannot pack closely, so oils rich in them stay liquid, such as sunflower, soybean, canola and olive oil, and the oil of fish and nuts.³ WHO prefers unsaturated fat to saturated fat, and says no more than 10 per cent of energy should come from saturated fat.³

Trans fat is the one to avoid. Most of it is made in factories when liquid vegetable oil is hardened, and hardened vegetable oil is what banaspati ghee has traditionally been. WHO says no more than 1 per cent of energy should come from trans fat of any kind, and that industrially produced trans fat is not part of a healthy diet and should be avoided.³ It hides in fried and baked food and in packaged snacks such as biscuits, cakes, wafers and frozen foods.

WHO’s practical advice is the advice to write in an answer.³ Steam or boil instead of frying. Replace butter, lard and ghee with oils rich in polyunsaturated fat such as soybean, canola, corn, safflower and sunflower. Choose lean meat and trim the visible fat, and cut down on fried snacks and packaged bakery goods.

9. Pakistan’s kitchen, where ghee came in and protein went out

The household survey shows how Pakistani diets have changed. Between 2018-19 and 2024-25, monthly consumption per person of vegetable ghee rose from 0.69 to 1.25 kilograms, an increase of about four fifths. Over the same years pulses fell from 0.35 to 0.26 kilograms, meat from 0.61 to 0.50, milk from 6.85 to 6.15, rice from 1.06 to 0.86 and wheat from 7.0 to 6.59.⁸

The Economic Survey’s own reading is that rising food prices and tight incomes are squeezing the variety of food families eat, with poorer households swapping nutritious food for cheaper food that is rich in energy but poor in nutrients.⁸ That is the sentence to carry into the hall. The cheapest source of energy pushed out the sources of protein, and a family can eat its fill of fried food and still be short of what a child needs to grow.

The same survey shows the price pressure month by month. The cost of a minimum food basket for one person rose from Rs 5,632 in July 2025 to a peak of Rs 6,417 in October 2025, nearly 14 per cent in three months, and was Rs 5,813 in March 2026.⁸ At the level of the whole country there is no shortage of energy, since food available per person came to about 2,550 kcal a day in 2025-26.⁸ The problem is how that food is shared and what it is made of.

10. Protein and the amino acids

Protein builds and repairs. Muscle, skin, the walls of every cell, the enzymes that digest food and the hormones that carry the body’s messages are all made of protein, and the body has no true store of it the way it stores fat.³¹⁰ So protein has to arrive regularly, and a growing child, a pregnant woman and a person recovering from illness need more of it.

Protein is built from amino acids, joined in long chains. Digestion takes protein apart into its amino acids, and the body builds its own proteins out of them.¹⁰ About twenty amino acids are common in food. Eight are essential for an adult, meaning the body cannot make them and food must supply them, and they are phenylalanine, tryptophan, methionine, lysine, leucine, isoleucine, valine and threonine. Histidine is a ninth, essential for infants and children because they need it to grow.¹⁰

A protein that carries all the essential amino acids in good proportion has a high biological value. Egg white and the protein of milk are the standard examples. Maize protein is low in tryptophan and lysine, and wheat protein is low in lysine, so both have a lower value.¹⁰ WHO adds that protein from animal food still matters for children and for pregnant and nursing women, while for adults in some settings more plant protein can lower the risk of heart disease and diabetes.³

11. Two poor proteins make one good one

Wheat protein is short of lysine, as the last section said. Pulses such as masoor, moong and channa are rich in lysine but short of methionine, which wheat carries well. Eat them together and each fills the other’s gap, so roti with daal gives a better protein than either alone.¹⁰ Rice with lentils and maize with beans work the same way.

This is the most useful point a candidate can make about protein in a poor country. It says the answer to a shortage of protein is not necessarily meat, which the poor cannot afford every day. It can be the combination they already cook, eaten at the same meal or on the same day, with a glass of milk or an egg when the family can manage it.

Too much protein is no help either. WHO notes that eating far more than needed puts an extra load on the body, especially the kidneys.³ The aim is enough protein, of good quality, from a mix of plant and animal food.

12. The vitamins, and vitamin A

Vitamins are substances the body needs in tiny amounts for its machinery to work. They are not grouped together because they are chemically alike, since they are not. Each was discovered through the disease its absence caused, and that is why the vitamins and their deficiency diseases are learned together.¹⁰

The division that matters is between fat-soluble and water-soluble vitamins. The fat-soluble vitamins are A, D, E and K. They dissolve in fat, they need some fat in the meal to be absorbed, and the body can store them, which cuts both ways, since a store carries a person through a lean season but a large dose can build up until it poisons. The water-soluble vitamins, the B group and C, are hardly stored, so they are needed often and are lost in cooking water that is thrown away.¹⁰

Vitamin A, or retinol, is part of the visual purple in the retina, so the eye cannot adjust to dim light without it. It also protects the surfaces of the body, the skin and the linings of the eye, gut and airways, and enough vitamin A lowers child deaths in poor populations, including deaths from measles.¹⁰ True vitamin A comes only from animal food, such as butter, eggs, milk, liver and fish. Most people in poor countries get theirs as beta-carotene, the orange pigment in carrots, mango, papaya, pumpkin, sweet potato and dark green leaves such as spinach and sarson, which the body turns into vitamin A. It takes about six micrograms of beta-carotene to make one microgram of retinol, and the change works badly in a diet with very little fat.¹⁰

Without vitamin A the eye fails in stages. Night blindness comes first, and the child becomes clumsy at dusk or cannot recognise people in a dim room. Then the white of the eye dries, which is called xerosis, and foamy triangular patches called Bitot’s spots appear. Then the clear front of the eye, the cornea, dries and ulcerates, and in the last stage, keratomalacia, it can soften and burst, and the eye is lost.¹¹

The detail worth a sentence in an answer is that the early stages are completely reversible with vitamin A by mouth. Once the cornea ulcerates, treatment can stop the damage but leaves a scar, and many children die at that stage because they are usually starving and infected as well.¹¹ In Pakistan’s 2018 survey, more than half of children under five, 51.5 per cent, were short of vitamin A.⁷

13. Vitamins D, E and K, and the danger of too much

Vitamin D controls how much calcium the body takes up from the gut and lays down in bone, so without it bone cannot use calcium properly however much the food contains.¹⁰ It comes from two places. Food supplies some, mainly fish liver oil, egg yolk, butter and fortified milk, while the skin makes it in sunlight, and for most people the sun is the larger source.¹⁰

Without vitamin D, children get rickets and adults get osteomalacia. In both the bone is short of calcium and becomes soft. In rickets the growing ends of the long bones swell, felt first at the wrist, beads form where the ribs meet their cartilage, and the legs bow under the child’s weight.¹¹ Rickets is a disease of children who eat almost no animal food and are kept out of the sun, and osteomalacia is commonest in women drained of calcium by several pregnancies who spend their days covered or indoors.¹¹ So a sunny country is no protection, and Pakistan’s 2018 survey found vitamin D deficiency in 62.7 per cent of children under five and 79.7 per cent of women of reproductive age.⁷

Vitamin E protects the fats in cell walls from damage by oxygen, and it comes from vegetable oils, nuts, seeds and green leaves. Its deficiency is rare in ordinary diets and appears mainly in babies born too early and in people who cannot absorb fat, which is why the textbooks give it little space.¹⁰ Say that plainly in an answer, because inventing a common deficiency disease for vitamin E is what loses the mark.

Vitamin K is needed to make the proteins that clot blood. It comes from green leafy vegetables, and bacteria in the large intestine make some of it for us.⁹ A shortage shows as bleeding that will not stop, seen in newborn babies whose gut bacteria are not yet settled, which is why a vitamin K injection at birth is routine, and in people on long courses of antibiotics.

Because the fat-soluble vitamins are stored, they can poison. The liver stores vitamin A, which is why fish liver oil is so rich in it, and too much vitamin A brings headache, vomiting, an enlarged liver, skin changes and hair loss. Cases from ordinary food are rare, but cases from supplements are not, and a high dose before or during pregnancy carries a high risk of birth defects.¹⁰ FPSC asked for this whole group in CE-2017, “What is the significance of Vitamins? Describe the sources, uses and deficiency symptoms of fat soluble vitamins.”²

14. The B vitamins

The B vitamins are a family of water-soluble vitamins that help the body release energy from food and make blood. Thiamine, vitamin B1, is used in the breakdown of carbohydrate. The nerves draw their energy from carbohydrate, so a shortage of thiamine starves them.¹⁰ Cereals and pulses are the richest sources, but most of the thiamine sits in the bran and germ of the grain, so heavy milling throws it away.¹⁰

A shortage of thiamine causes beriberi, in three forms.¹¹ Wet beriberi attacks the heart, with swelling, breathlessness and a danger of sudden death. Dry beriberi attacks the nerves, with weak, wasted legs and loss of feeling. Infantile beriberi strikes a breastfed baby whose mother is short of thiamine, and it is the only serious deficiency disease that commonly appears in an otherwise normal baby under six months.¹¹

The disease taught the world what a vitamin was. In the 1890s in Java, Christiaan Eijkman fed chickens the polished white rice his beriberi patients ate, and the chickens developed the same weak legs, while whole-grain rice cured them.¹⁰ A milling decision had become a disease. The cooking rule follows from it, since thiamine dissolves in water and is destroyed by strong heat, so rice should be cooked in just the water it will absorb, and the water in a stew should be eaten rather than poured away.¹⁰

Riboflavin, vitamin B2, also works in releasing energy, and milk, meat, eggs and green leaves carry it. A shortage cracks the corners of the mouth and leaves a sore tongue and cracked lips, a common condition that is not dangerous.¹⁰ Niacin is another energy vitamin, and a shortage causes pellagra, remembered by three Ds, dermatitis, diarrhoea and dementia. Its skin sores appear on the parts exposed to sunlight, and it belongs to maize-eating peoples as beriberi belongs to rice-eating ones, because the body can make niacin from tryptophan and maize protein is poor in tryptophan.¹¹

Vitamin B12 and folate are both needed to make red blood cells, and a shortage of either causes a megaloblastic anaemia, in which the red cells are too few and too large. Vitamin B12 comes almost only from animal food, so years of a strict vegetarian diet with no milk or eggs can cause it.¹⁰ Folate comes from green leaves and pulses, and a woman short of it around the start of pregnancy risks a baby with a defect of the spine or brain.³

15. Vitamin C

Vitamin C, or ascorbic acid, builds and maintains the material between cells, which acts like cement holding the tissues together. It also helps the body absorb iron from plant food.¹¹ Fresh fruit and vegetables supply it, and guava, amla, citrus, tomato and raw cabbage are especially rich. It is destroyed by long cooking and long storage, which is why fresh, lightly cooked or raw food matters.

A long shortage causes scurvy. The walls of the tiny blood vessels weaken and bleed, the gums swell and bleed, wounds refuse to heal, and bleeding appears under the skin and around the bones. In a baby the classic sign is pain on being picked up, because blood has collected under the covering of the bones.¹¹ The disease was the curse of long sea voyages, and the British navy’s issue of lemons and limes to its sailors was its cure.¹¹

Severe scurvy is now uncommon, but intakes well below the level a person needs are common across Asia and Africa.¹¹ So the honest sentence for an answer is that the classical disease is rare while mild shortage is widespread. It matters most for iron, the next section’s subject, since a squeeze of lemon on the daal lets the body take in more of the daal’s iron.

16. Iron and anaemia

Iron is the working part of haemoglobin, the substance in red blood cells that carries oxygen from the lungs to every part of the body.¹⁰ Without enough iron the blood carries less oxygen, and that is anaemia. WHO lists its signs as tiredness, a reduced ability to do physical work and shortness of breath, and in a young child severe anaemia can hold back the development of the brain and body.⁵

Iron comes from red meat, fish, poultry, pulses, fortified cereals and dark green leaves, but the amount in the food is not the amount that reaches the blood. Iron from meat and fish is absorbed far better than iron from plants. Vitamin C in the same meal raises absorption, while tea, coffee, cocoa, calcium and the bran of whole cereals lower it if eaten with the iron-rich food.⁵

So a cup of tea with the meal can undo part of the iron in the meal. A cup an hour later does no harm, and a lemon squeezed on the daal helps. That is the practical advice an examiner looks for, and it costs a family nothing.

WHO estimates that anaemia affects about half a billion women aged 15 to 49 and 269 million children aged 6 to 59 months, about 40 per cent of all young children, with a poor diet short of iron as the most common nutritional cause.⁵ In Pakistan the 2018 survey found 53.7 per cent of children under five anaemic and 41.7 per cent of women of reproductive age.⁷ Pregnant women, menstruating girls and young children are most at risk, since their bodies need more iron than a poor diet supplies.⁵

17. Iodine, calcium and zinc

The body of an adult holds only 20 to 50 milligrams of iodine, most of it in the thyroid gland in the neck, which needs it to make its hormones.¹⁰ Those hormones set the pace at which the whole body works and govern the growth of a baby’s brain. Without iodine the thyroid swells into a goitre, but that is only the visible part of a wider set called iodine deficiency disorders, which include stillbirth, poor growth, cretinism and a loss of mental ability across a whole population.¹¹

Cretinism is the worst of them, a child born with profound mental disability, often unable to walk properly. In every form the brain damage and stunted growth cannot be reversed, because the harm was done before birth. So the only real answer is prevention, making sure women who may become pregnant are not short of iodine.¹¹ Iodised salt is the cheapest way, and Pakistan’s 2018 survey found that about four households in five used it, but only 31.6 per cent in the merged districts of Khyber Pakhtunkhwa, against over 85 per cent in Islamabad, Punjab, Azad Jammu and Kashmir and Gilgit-Baltistan.⁷

Calcium builds bones and teeth and is needed for muscles to contract and blood to clot.¹⁰ Milk, yoghurt, cheese, small fish eaten with their bones and green leaves supply it. Its use depends on vitamin D, which is why a child kept out of the sun can get rickets on a diet rich in calcium. Pakistan’s 2018 survey found low blood calcium in 26.5 per cent of women of reproductive age.⁷

Zinc is needed for growth, for the body’s defence against infection and for wounds to heal, and meat, fish, eggs, pulses and whole grains carry it. A shortage slows a child’s growth and makes diarrhoea last longer, which is why zinc is given with oral rehydration salts. Pakistan’s survey found zinc deficiency in 18.6 per cent of children under five.⁷

18. Salt, potassium, fibre and water

Sodium and potassium are both essential minerals, and the trouble is the balance between them. A high intake of sodium, which almost always means salt, raises blood pressure, and high blood pressure leads to heart disease and stroke. Potassium softens sodium’s effect on blood pressure, and fresh fruit and vegetables supply it.³ WHO’s limit for adults is less than 5 grams of salt a day, which is 2 grams of sodium, and it suggests at least 3,510 milligrams of potassium.³ The practical steps are to use less salt in cooking, keep no salt on the table, eat fewer salty snacks and read labels.

Dietary fibre is the part of plant food the gut cannot digest. It adds bulk and holds water, so it keeps the bowel moving, it feeds the helpful bacteria of the large intestine, and it slows the rise of sugar in the blood after a meal. WHO says everyone over ten should aim for at least 25 grams of naturally occurring fibre a day, with at least 15 grams for children of 2 to 5 and 21 grams for those of 6 to 9.³ Whole wheat flour, brown rice, pulses, vegetables and fruit are the sources, while finely milled white flour has lost much of its fibre.

Water is the medium every reaction in the body happens in. It carries nutrients and waste and controls body heat through sweat, and an adult loses it all day in urine, breath and through the skin. Safe water belongs in a nutrition answer too. In 2024, 90.7 per cent of Pakistanis had at least basic drinking water and 71.9 per cent at least basic sanitation, against 95.9 and 82.0 per cent for South Asia.⁸ Dirty water causes diarrhoea, diarrhoea causes wasting, and wasting is malnutrition, so an answer that mentions water and sanitation is describing how malnutrition actually happens.

19. How the body takes food apart

Every nutrient so far has to get from the plate into the blood, and that is the work of the digestive system. It is one long tube, the mouth, oesophagus, stomach, small intestine, large intestine and anus, with three solid organs beside it, the liver, the gall bladder and the pancreas. The small intestine has three parts, the duodenum, jejunum and ileum, and the large intestine takes in the caecum, colon and rectum.⁹ FPSC asked about this journey in CE-2018 and again in CE-2023, “How the carbohydrates, proteins, and fats are digested in humans?”²

Follow a mouthful of roti and daal. In the mouth, chewing breaks it up and saliva wets it and carries an enzyme that starts breaking down starch.⁹ The oesophagus pushes it down to the stomach, where glands in the lining add acid and enzymes and the muscle churns them in. Here the breakdown of protein begins, and the stomach slowly empties a half-digested mush, called chyme, into the small intestine.⁹

The small intestine does most of the work. Juices arrive from three directions. The pancreas sends enzymes for carbohydrate, fat and protein. The liver sends bile, stored in the gall bladder, which digests no food itself but breaks fat into tiny droplets that the enzymes can reach, and the intestine’s own wall adds more enzymes and then absorbs the finished nutrients.⁹ What is left passes to the large intestine, which takes water back into the blood, while its bacteria break down some of the rest and make vitamin K. The remainder becomes stool.⁹

Each energy nutrient ends as something small enough to absorb. Carbohydrate begins in the mouth and ends in the small intestine as single sugars, mainly glucose. Protein begins in the stomach and is finished by enzymes from the pancreas and the intestine, ending as amino acids.¹⁰ Fat waits for the small intestine because it needs bile first, and it ends as fatty acids and glycerol.

The roads they take differ too. Blood from the small intestine carries the sugars, amino acids, glycerol and some vitamins and salts to the liver, which stores and processes them and releases them as the body needs them. Fatty acids and the fat-soluble vitamins go into the lymph first and reach the blood later.⁹ That difference explains why fat digestion fails so completely when bile is missing, and why a person who cannot absorb fat becomes short of vitamins A, D, E and K.

20. The food groups, and Pakistan’s own plate

Nutrients are not bought in the bazaar, foods are, so the advice has to be given as food groups. FPSC asked for exactly this in CE-2025, “Enlist major food groups based on nutrients, their functions and sources.”² Five groups cover the ground for most answers, each with its main nutrients and the foods a Pakistani family knows.

Write it as three columns in the examination, as the question asks. Name the group, name the nutrients and their job, name the foods. A list of foods with nothing about what they supply answers only half the question.

Pakistan has its own national advice, and naming it lifts an answer above a general one. The Pakistan Dietary Guidelines for Better Nutrition were launched in Islamabad on 19 December 2018 by the Ministry of Planning, Development and Reform with FAO.¹² They replaced the first national guidelines, written by the Ministry of Health in 2005.¹³ The guidelines draw a balanced diet as one plate divided into six groups, cereals, meat and pulses, milk and milk products, vegetables, fruits, and fats and oils, with fats and oils on the plate because they are part of every Pakistani meal. The cereals, the main staple, supply over half of the body’s energy.¹³

The guidelines end with plain messages for families.¹³ Keep a normal body weight by eating from all the groups and staying active, and make half of your cereals whole grains. Eat five servings of fresh vegetables and fruit a day, two to three servings of milk and milk products, and meat, fish and eggs in moderation with more pulses. Use fortified flour, less oil, sugar, salt and soft drinks, and always iodised salt.

A serving is something a family can measure at the table. One serving of cereal is one chapati or one cup of cooked rice, one serving of milk is one cup of milk or yoghurt, and one serving from the meat group is about 28 grams of lean meat, one egg or half a cup of cooked pulses.¹³

21. Building a cheap balanced day

A candidate who can build a balanced day from ordinary food earns more than one who can only list nutrients, so here is one worked out. In the morning, roti with a glass of milk or a boiled egg gives energy from the roti and protein and vitamin B12 from the milk or egg. At midday, roti with daal, a seasonal vegetable and a squeeze of lemon gives a complete protein from the wheat and pulse together, while the lemon raises the absorption of the daal’s iron.¹⁰⁵

In the evening, rice or roti with a green leafy vegetable cooked in a spoon of oil and a bowl of yoghurt completes the day. The oil carries the vegetable’s beta-carotene into the body and the yoghurt adds calcium. Between meals, a seasonal fruit such as guava in winter or mango in summer replaces a packaged snack, and clean water is drunk through the day, with tea taken an hour after the meal rather than with it.⁵

Nothing on that list is expensive and every item is in an ordinary bazaar, which is the point to make. Count it against the guidelines’ messages and it meets most of them, cereals at every meal, pulses daily, milk twice, vegetables and fruit, and little fried food or sugar.¹³ The examiner is looking for a candidate who can turn nutrition into advice a poor household can follow.

Now plan one yourself. A family in Thar can afford roti, millet, daal, onions, a little milk, chillies and seasonal melons, but rarely meat or eggs. Using the three jobs of food, say what each meal should hold and which nutrient the family is most likely to run short of, before opening the answer.

22. Diet through life

A balanced diet is not the same at every age, because the body’s needs change. A baby should have only breastmilk for the first six months, and then other food as well, with breastfeeding continued to two years and beyond.³ Growing children and teenagers need more energy, protein, calcium and iron, and girls need more iron once their periods begin. WHO adds that the habits formed in childhood often last into adult life, which is why school food and what children see at home matter so much.³

Pregnancy costs a mother about 80,000 kcal in all, which comes to about 300 kcal a day, and Pakistan’s guidelines advise 300 kcal a day more in the second and third trimesters, with 7 and 23 grams a day of extra protein.¹³ A woman of normal weight should gain about 12 kilograms.¹³ Iron and folate matter most, because the baby’s blood and nervous system are being formed, and an anaemic mother is more likely to have a small, weak baby.

A nursing mother needs about 500 kcal a day more, with 19 grams of extra protein in the first six months of breastfeeding and 13 grams in the second six.¹³ In old age taste weakens, digestion slows and long-term illness is common, so older people need enough protein, fibre, vitamins, minerals and fluid, which prevents constipation and protects their bones against falls.¹³

23. Malnutrition and its forms

Malnutrition means any shortage, excess or imbalance in a person’s energy or nutrients, and WHO sorts it into three broad groups.⁴ The first is undernutrition, measured three ways, wasting, which is low weight for height, stunting, which is low height for age, and underweight, which is low weight for age. The second is micronutrient malnutrition, a shortage or excess of vitamins and minerals, often called hidden hunger because a child can look well fed and still lack them. The third is overweight, obesity and the diet-related diseases that follow, heart disease, stroke, diabetes and some cancers.

The two measures of undernutrition tell different stories, and mixing them up costs marks. Wasting usually means recent and severe weight loss, after too little food or an illness such as diarrhoea, and a wasted child has a raised risk of death, though treatment is possible.⁴ Stunting is the result of long-term or repeated undernutrition, usually with poverty, a poorly nourished mother, frequent illness and poor feeding in early life, and it holds children back from reaching their full physical and mental growth.⁴

Severe undernutrition in a child takes two named forms. In kwashiorkor the hallmark is swelling, called oedema, which leaves a dent when the foot is pressed with a thumb. The child also shows poor growth, wasted muscles, a fatty liver, changes in the hair and skin, anaemia, diarrhoea and a dull, unhappy manner, and the swelling can make the child look well fed, which is why the disease was missed for so long.¹¹

In marasmus the overwhelming sign is severe underweight, a child reduced to skin and bone with no swelling. It is a form of starvation, a shortage of food and so of energy in general, and it is commoner in the first year of life and now commoner than kwashiorkor in most countries.¹¹ Both usually come with infection, since diarrhoea, chest infections, measles, whooping cough and worms are common triggers, partly by killing the appetite, and both usually carry vitamin and mineral shortages too.¹¹

The toll is heavy. WHO says nearly half of all deaths among children under five are linked to undernutrition, mostly in low and middle income countries. In 2022, 149 million children under five were stunted, 45 million were wasted and 37 million were overweight, while 390 million adults were underweight.⁴

24. Measuring weight, the body mass index

Overweight and obesity are measured with the body mass index, or BMI, which is a person’s weight in kilograms divided by the square of their height in metres.⁶ For adults, WHO calls a BMI of 25 or more overweight and a BMI of 30 or more obese.⁶ For children and teenagers aged 5 to 19 the fixed numbers do not work, so WHO compares a child’s BMI with the middle value for their age and sex instead.⁶

Work one through. A man weighs 70 kilograms and is 1.65 metres tall. His height squared is 1.65 × 1.65 = 2.72, and 70 ÷ 2.72 gives a BMI of about 25.7, so he is just overweight. At his height, 68 kilograms would bring him to a BMI of 25, and 82 kilograms would make him obese.

BMI is a first screening test, not a diagnosis. It does not tell fat from muscle, so a wrestler can score as overweight, and it says nothing about where the fat sits, though fat around the waist carries more risk than fat on the hips. WHO notes that waist size can also be used.⁶

Obesity is rising across the world. WHO counts 1.1 billion people living with obesity in 2024, one person in seven, with adult obesity more than doubled since 1990 and obesity among teenagers four times higher.⁶ In 2024, 2.6 billion adults were overweight, 45 per cent of all adults, and 940 million of them were obese.⁶ It drives type 2 diabetes, heart disease, liver and kidney disease and several cancers, which is why WHO calls it a major public health challenge.⁶

25. Where Pakistan’s nutrition stands

The National Nutrition Survey 2018 is Pakistan’s own measurement, carried out by the Government of Pakistan with UNICEF. It is the fifth national nutrition survey since 1965 and the first to give figures for every district, and no newer survey of its kind has been published, so its figures are still the ones to quote with their year.⁷ It found 40.2 per cent of children under five stunted, ranging from 32.6 per cent in Islamabad to 48.3 per cent in the merged districts of Khyber Pakhtunkhwa, 28.9 per cent underweight and 9.5 per cent overweight.⁷

Its most alarming figure was wasting, at 17.7 per cent, up from 8.6 per cent in 1997 and 15.1 per cent in 2011.⁷ Stunting tells a longer story. It improved from 48 per cent in 1965 to 36.3 per cent in 1994, worsened to 41.6 per cent in 2001 and 43.7 per cent in 2011, and stood at 40.2 per cent in 2018, which the survey calls a critical level by global standards.⁷

Hidden hunger is as widespread. More than half of young children were anaemic or short of vitamin A, and four women in five lacked vitamin D, in one of the sunniest countries on earth.⁷ WHO finds the same pattern worldwide, with more than half of children under five and over two thirds of women short of at least one key micronutrient, usually iron, zinc, vitamin A or folate.³

Pakistan also carries the opposite problem. The same survey found 14.4 per cent of women of reproductive age undernourished, down from 18 per cent in 2011, while overweight and obesity among them rose from 28 to 37.8 per cent, and among teenagers 11.4 per cent of girls and 10.2 per cent of boys were overweight.⁷ This is the double burden of malnutrition, too little and too much in the same country and sometimes in the same household.

The Economic Survey 2025-26 sets Pakistan beside South Asia on World Bank figures. Stunting stood at 33.6 per cent against 31.5 per cent for the region in 2024, a modelled estimate rather than a fresh survey, and undernourishment at 16.5 per cent against 11.7 in 2023, while basic sanitation reached 71.9 per cent of people against 82.0.⁸ On these measures Pakistan is behind its own region, which is the comparison an examiner is waiting for.

26. What Pakistan is doing

An answer that names programmes reads like one written by a candidate who has read the file. The Benazir Nashonuma Programme serves pregnant and nursing women and young children, to prevent stunting and low birth weight, reduce anaemia and other shortages of vitamins and minerals, and bring more mothers to nutrition services. Its midline evaluation found stunting 6.4 percentage points lower among children under two in the programme and low birth weight 5.6 points lower.⁸

The National Multisectoral Nutrition Programme aims at stunting in poor and flood-hit districts, and a pilot in seven districts, SOPRAN, gave adolescent girls weekly iron and folic acid and promoted fortified wheat flour.⁸ In Azad Jammu and Kashmir alone, more than 3,000 Lady Health Workers bring iron supplements, care in pregnancy and advice on spacing births to women at home.⁸ Salt iodisation remains the cheapest and most effective step against iodine deficiency, and the 2018 guidelines tell every family to use iodised salt and fortified flour.¹¹¹³

The provinces run their own programmes as well, such as stunting prevention and school nutrition in Khyber Pakhtunkhwa and livestock given to rural women in south Punjab.⁸ The test for all of them is whether the next national survey shows stunting and wasting falling, and that is the figure a strong answer promises to watch.

27. Where things stand now

These are the latest positions as of 7 October 2026. The National Nutrition Survey 2018 is still Pakistan’s latest national measure, with stunting at 40.2 per cent and wasting at 17.7 per cent, while the World Bank’s modelled estimate puts stunting at 33.6 per cent in 2024.⁷⁸ The 2024-25 household survey shows ghee up and pulses, milk and meat down since 2018-19, and the Nashonuma programme reports stunting 6.4 points lower among the children it reaches.⁸

Worldwide, WHO’s updated healthy diet advice of January 2026 puts carbohydrate at 45 to 75 per cent of energy, keeps free sugars under 10 per cent, fat at 15 to 30 per cent with saturated fat under 10 and trans fat under 1, and salt under 5 grams.³ WHO’s obesity figures for 2024 count 1.1 billion people with obesity, one in seven.⁶

28. What people get wrong about food

The commonest mistake is to think malnutrition means not enough food, when WHO’s own definition includes overweight, obesity and the diseases that follow.⁴ The next is to think a balanced diet is expensive. Roti with daal, a seasonal vegetable and a glass of milk make a balanced meal from the cheapest foods in the bazaar, and meat every day is not what nutrition requires.

Some students write that fat should be cut out, when two fatty acids can only come from food and the fat-soluble vitamins need fat to be absorbed, so the advice is 15 to 30 per cent of energy, not zero.³ Others call ghee natural and therefore healthy, when hardened vegetable ghee is a source of the trans fat WHO says should be avoided.³ Many believe a sunny country cannot be short of vitamin D, when Pakistan’s own survey found it in four women in five.⁷

Spinach is often called the best source of iron, but iron from leaves is absorbed far less well than iron from meat, and tea with the meal lowers it further.⁵ Vitamins are thought harmless, so more must be better, when the fat-soluble ones build up and too much vitamin A in pregnancy can harm the baby.¹⁰ Last, stunting is not just short height. It is the visible sign that a child’s growth and brain have already been held back.⁴

29. What the examiners have asked

These are the part-questions from the eleven papers from CE-2016 to CE-2026 that this chapter answers.²

• CE-2016, Q.5(b). “What is Cholesterol? Discuss its importance, normal blood level and dangers of elevated levels with reference to the health and disease in humans.” Use the sections on fats and on saturated and trans fat for the diet side; the blood levels belong to the chapter on human physiology.
• CE-2017, Q.3(D). “What is the significance of Vitamins? Describe the sources, uses and deficiency symptoms of fat soluble vitamins.” The sections on vitamin A and on vitamins D, E and K.
• CE-2018, Q.3(C). “Define ‘Carbohydrates’. Describe different steps to digest these in the human body.” The sections on carbohydrates and on how the body takes food apart.
• CE-2018, Q.5(C). “Write a comprehensive note on ‘Balanced Diet’.” The sections on what a balanced diet is, the food groups and one Pakistani figure.
• CE-2019, Q.2(a) and (b). A table of five diseases to match with the missing vitamin, and how cholesterol building up in arteries harms the heart. The vitamin sections and the section on fats.
• CE-2020, Q.3(b). “What are carbohydrates? Classify and give detail of each class along with examples.” The section on carbohydrates and their three classes.
• CE-2021, Q.5(a). “Define the term “malnutrition”. Elaborate its major causes and consequences.” The section on malnutrition, with Pakistan’s figures.
• CE-2023, Q.5(b). “How the carbohydrates, proteins, and fats are digested in humans?” The section on how the body takes food apart.
• CE-2024, Q.4(a). “What is role of Carbohydrates and Vitamins in the body? Discuss briefly.” The sections on carbohydrates and on the vitamins.
• CE-2025, Q.5(b). “Enlist major food groups based on nutrients, their functions and sources.” The table of food groups.

Read the verb before you plan. “Enlist” wants a list, so give a table, while “elaborate” wants causes and consequences developed in paragraphs. “Describe the sources, uses and deficiency symptoms” is three demands, so answer each vitamin in three parts.

30. Facts to take into the examination hall

• Energy: carbohydrate and protein about 4 kcal a gram, fat about 9; 1 kcal is 4.184 kJ.¹⁰
• WHO for an adult: carbohydrate 45 to 75 per cent of energy; fat 15 to 30 per cent, saturated under 10, trans under 1; protein 10 to 15 per cent, about 50 to 75 g; free sugars under 10 per cent, about 50 g or 12 teaspoons; fruit and vegetables at least 400 g; fibre at least 25 g; salt under 5 g, which is 2 g of sodium; potassium at least 3,510 mg.³
• Amino acids: about twenty common, eight essential for adults, histidine a ninth for children.¹⁰
• Carbohydrates: monosaccharides (glucose, fructose, galactose), disaccharides (sucrose, lactose, maltose), polysaccharides (starch, glycogen, cellulose).¹⁰
• Deficiencies: vitamin A, night blindness to keratomalacia; B1, beriberi; B2, cracked lips; niacin, pellagra; B12 or folate, megaloblastic anaemia; C, scurvy; D, rickets and osteomalacia; K, bleeding; iron, anaemia; iodine, goitre and cretinism; zinc, poor growth.¹⁰¹¹
• Pakistan 2018: stunting 40.2, wasting 17.7, underweight 28.9, overweight 9.5 per cent of children under five; anaemia 53.7, vitamin A deficiency 51.5, vitamin D deficiency 62.7, zinc deficiency 18.6 per cent; women’s vitamin D deficiency 79.7 and anaemia 41.7 per cent.⁷
• Pakistan against South Asia: stunting 33.6 against 31.5 per cent (2024, modelled), undernourishment 16.5 against 11.7 per cent (2023).⁸
• Household change, 2018-19 to 2024-25, kg per person per month: ghee 0.69 to 1.25, pulses 0.35 to 0.26, meat 0.61 to 0.50, milk 6.85 to 6.15, sugar 1.28 to 1.22.⁸
• Pakistan Dietary Guidelines: launched 19 December 2018; six groups on one plate; five servings of fruit and vegetables and two to three of milk a day; pregnancy 300 kcal a day extra, breastfeeding 500.¹²¹³
• BMI: weight in kg divided by height in metres squared; overweight 25 or more, obese 30 or more. Obesity in 2024: 1.1 billion people, one in seven.⁶

31. What loses marks on this subject

Listing nutrients without their jobs loses most of the marks, since the question almost always asks what each one is for. Naming a deficiency disease without its signs earns little, so write “night blindness first, then drying of the eye with Bitot’s spots, then ulcers of the cornea”, not “eye problems”. Treating malnutrition as hunger alone throws away the hidden hunger and the obesity side.

Undated figures read as guesses, so write “stunting was 40.2 per cent in the National Nutrition Survey 2018”, not “stunting is very high”. Foreign examples where Pakistani ones exist waste a chance, since the examiner is choosing Pakistani officers, so use the merged districts, iodised salt, Nashonuma and the Lady Health Workers. A doctor’s answer full of treatment misses the officer’s answer the paper rewards, which is prevention, fortification, clean water and the programmes that deliver them.

Last, mixing up the two pairs costs marks in an answer that is otherwise right. Stunting is low height for age and means the long term, wasting is low weight for height and means now. Kwashiorkor has swelling and marasmus is extreme thinness.

32. A worked answer plan

The question is CE-2021, Q.5(a), “Define the term “malnutrition”. Elaborate its major causes and consequences.” It carries five marks, about seven minutes of writing, so plan four short paragraphs and a closing line.²

Open with the definition. Malnutrition is a shortage, excess or imbalance of energy or nutrients, and WHO’s definition covers undernutrition, meaning wasting, stunting and underweight, micronutrient malnutrition, and overweight and obesity with the diseases that follow.⁴ Add one line that a country can carry undernutrition and obesity at once, and Pakistan does.

Give the causes in three layers. The immediate causes are too little food, food of the wrong kind, and infection, since diarrhoea and measles destroy appetite and waste the body.¹¹ Beneath them lie poverty, food prices, unsafe water and poor sanitation, and feeding practices such as weaning too early. At the root lie the mother’s own health and education, since a stunted, anaemic mother bears a small baby.

Then give the consequences for the person and the country, with figures. Wasting raises the risk of death, stunting holds back growth and the brain, and iodine shortage in pregnancy causes damage that cannot be undone.⁴¹¹ In Pakistan stunting was 40.2 per cent and wasting 17.7 per cent in 2018, with anaemia in more than half of young children, and Pakistan is behind South Asia on stunting and undernourishment.⁷⁸ A stunted generation is a less productive workforce, which makes malnutrition an economic problem and not only a health one.

Close with the remedy in one line, naming measures that work at scale and cost little, salt iodisation, fortified flour and support in the first thousand days through programmes such as Benazir Nashonuma, which reports stunting 6.4 points lower among the children it reaches.⁸ The plan scores because it defines before it describes, separates causes from consequences as “elaborate” asks, carries dated Pakistani figures and ends with policy.

What to remember from this chapter

1. A balanced diet gives every nutrient in the right amounts, from food a person can get. Adequacy, balance, moderation and diversity are WHO’s four principles.
2. Six classes of nutrient, with fibre named separately because FPSC names it.
3. Carbohydrate and protein give about 4 kcal a gram, fat about 9.
4. Carbohydrates are monosaccharides, disaccharides and polysaccharides, three examples each.
5. Fat is essential. The limits are 15 to 30 per cent of energy, saturated under 10, trans under 1.
6. Protein quality depends on amino acids, and roti with daal is the pair that completes each other.
7. Vitamins A, D, E and K need fat, are stored, and can poison in excess.
8. Each deficiency has a named disease with named signs.
9. Iron depends on absorption. Vitamin C helps, tea with the meal hinders.
10. Iodine damage from before birth cannot be undone, so prevention is the only answer.
11. Digestion runs mouth for starch, stomach for protein, small intestine for all three with bile and pancreatic juice, large intestine for water.
12. Pakistan’s own guidelines of 2018 draw six food groups on one plate.
13. Stunting is low height for age, wasting low weight for height; kwashiorkor swells, marasmus wastes.
14. BMI is weight divided by height squared; adults are overweight at 25 and obese at 30.
15. Pakistan carries a double burden, 40.2 per cent stunting in 2018 beside rising overweight among women.

Check yourself

Answer each from memory, in your own words, before you open the answer.

1. Define a balanced diet, and name WHO’s four principles of a healthy diet. (The section on what a balanced diet is.)

2. A meal holds 40 grams of carbohydrate, 20 grams of protein and 15 grams of fat. How much energy does it give, and what share comes from fat? (The section on energy.)

3. Classify carbohydrates into three classes with an example of each, and say which class the body cannot digest at all. (The section on carbohydrates.)

4. Why is ghee solid and sunflower oil liquid, and which kind of fat does WHO say to avoid altogether? (The section on saturated, unsaturated and trans fat.)

5. Why is roti with daal a better protein than roti alone? (The section on two poor proteins.)

6. Describe how vitamin A deficiency damages the eye, and say which stages can be reversed. (The section on vitamin A.)

7. Why do Pakistani women, in a sunny country, so often lack vitamin D? (The section on vitamins D, E and K.)

8. What did Eijkman’s chickens show, and what cooking rule follows? (The section on the B vitamins.)

9. Name two things that raise the absorption of iron and two that lower it. (The section on iron and anaemia.)

10. What is the difference between goitre and cretinism, and why is prevention the only answer to cretinism? (The section on iodine, calcium and zinc.)

11. Trace a mouthful of roti from the mouth to the blood. (The section on how the body takes food apart.)

12. What is the difference between stunting and wasting, and between kwashiorkor and marasmus? (The section on malnutrition and its forms.)

13. Work out the BMI of a woman who weighs 58 kilograms and is 1.55 metres tall, and say what it means. (The section on the body mass index.)

14. Give Pakistan’s stunting, wasting and child anaemia figures, with their source and year. (The section on where Pakistan’s nutrition stands.)

15. From the chapter on water pollution, how many deaths a year does WHO link to unsafe drinking water alone, and why does it belong in an answer on malnutrition? (An earlier chapter.)

16. From the chapter on population planning, how long does a population growing at 2 per cent a year take to double? (An earlier chapter.)