Basic concepts

A calorie is a unit used to express energy. In nutrition, food energy is commonly reported in kilocalories, although people often call them simply calories. Carbohydrates and proteins provide about four kilocalories per gram, while fat provides about nine. Thus, calorie measures energy, so option D is correct.

Macronutrients are nutrients required in relatively large amounts because they provide energy and/or major building material. The principal macronutrients are carbohydrates, proteins and fats; water is also required in large amounts, though it provides no calories. Vitamins and minerals are generally classified as micronutrients. Therefore, option A is correct.

Micronutrients are vitamins and minerals required in small quantities, but they are essential for regulating metabolism, immunity, blood formation, vision and many other functions. Carbohydrates, proteins and fats are macronutrients because the body needs them in larger amounts. Hence, vitamin is the correct example and option B is unambiguous.

Protein supplies amino acids needed to build and repair muscles, skin, organs, enzymes, hormones and other body tissues. Children, adolescents, pregnant people and individuals recovering from illness may have especially important protein needs. Although all nutrients contribute to health, protein has a direct body-building role, making option C correct.

A therapeutic diet is a normal diet modified in nutrients, texture, consistency, timing or feeding pattern to meet the needs created by a disease or medical treatment. Examples include a low-sodium diet for some patients with hypertension or a soft diet when chewing is difficult. It supports treatment but does not automatically replace medicines. Option B is correct.

Milk and many milk products provide high-quality protein and calcium. Protein supports growth and tissue repair, while calcium is important for bones and teeth and also contributes to muscle and nerve function. The exact nutrient content varies with processing and product type, but calcium and protein are the key school-level association. Therefore, option C is correct.

Cereals such as rice, wheat, maize and millet are major sources of carbohydrates, especially starch. Carbohydrates are broken down to provide energy for physical activity, brain function and basic metabolism. Whole or less-refined cereals also contribute fibre, vitamins and minerals, but their main nutritional contribution is energy-giving carbohydrate. Hence, option D is correct.

Pulses such as lentils, chickpeas, peas and beans are important plant sources of protein. Protein supplies amino acids for growth, tissue repair, enzymes and body maintenance. Pulses also provide complex carbohydrate, fibre, iron and other nutrients, but their well-known school-level classification is as body-building protein foods. Therefore, option A is correct.

Energy balance means that energy supplied by food and beverages is approximately equal to energy used for basal metabolism, physical activity, growth and other body functions. When intake exceeds expenditure over time, weight may increase; when expenditure exceeds intake, weight may decrease. Thus A is correct.

If energy intake remains greater than energy expenditure, the body stores part of the surplus, mainly as body fat. Over time this positive energy balance can cause weight gain, although the exact result also depends on activity, metabolism and health. Therefore D is the only relevant answer.

Nutritional status is the current condition of a person in relation to nutrient intake, absorption and use by the body. It reflects whether energy and nutrients are adequate, deficient or excessive. Health workers assess it using diet history, clinical signs, anthropometry and sometimes laboratory tests. Thus B is correct.

Nutritional assessment systematically collects information about dietary intake, body measurements, clinical signs, health history and sometimes laboratory values. It helps identify deficiency, excess, malnutrition and individual dietary needs, so an appropriate nutrition plan can be prepared. Therefore C is correct.

Anthropometry is the measurement of the human body and its physical dimensions. Height, weight, body-mass index, mid-upper-arm circumference and skinfold thickness are commonly used in nutrition assessment. Smell, kitchen size and plate shine do not measure a person’s body, so height and weight are the correct example.

A deficiency disease develops when the diet or body supply lacks a nutrient required for normal function. For example, inadequate iron may cause anaemia, vitamin C deficiency may cause scurvy and vitamin D deficiency may impair bone health. Thus lack of an essential nutrient, option D, is correct.

Controlling portion size helps match food intake with age, sex, activity, health condition and nutritional requirements. Very large portions may provide excess energy, fat, sugar or salt, while very small portions may cause inadequate nutrient intake. Appropriate quantity supports balance and health, so B is correct.

Cooking can destroy many disease-causing microorganisms, soften food, improve flavour and make some nutrients more accessible or foods easier to digest. The exact effect depends on the method and duration of cooking, but improving safety and digestibility is a recognised purpose. Hence B is correct.

Energy-yielding nutrients fuel body functions, physical activity, growth and maintenance. Protein supplies amino acids needed to build and repair muscles, organs, enzymes and other tissues. Protein can also provide energy, but its main importance is growth and repair. Therefore B correctly states the complementary roles of both.

Local foods are often available in nearby markets, familiar to the community and less expensive because transport and storage costs may be lower. They can also be nutritious when selected from a variety of food groups. Local preference does not guarantee quality, but accessibility and affordability make C correct.

Seasonal produce is generally harvested during its natural growing period and may be fresher, more available and less costly. Fruits and vegetables contribute vitamins, minerals, fibre and beneficial plant compounds. They should still be washed and handled safely, but their possible freshness and nutrient value make D correct.

Positive energy balance occurs when energy intake is greater than energy expenditure over time. The body does not waste all of the surplus; some may be stored, largely as body fat. If this pattern persists, body weight can increase, although the exact change also depends on metabolism, activity, health and individual circumstances.

Negative energy balance means that, over a period of time, the energy obtained from food is lower than the energy used for basal metabolism, physical activity and other body processes. The body may then draw on stored glycogen and fat, so sustained negative balance can contribute to weight loss.

Water-soluble vitamins such as vitamin C and most B vitamins circulate in body fluids and are not retained in large reserves for long periods. Excess is commonly excreted, so regular intake from a varied diet is important. Inadequate intake over time can reduce body availability and produce deficiency symptoms, although storage and excretion differ somewhat among individual vitamins.

Thiamine is vitamin B1, a water-soluble member of the B-complex group. It participates in carbohydrate metabolism and helps enzymes release energy from food; it also supports normal nerve and heart function. It is therefore classified as a vitamin, not as a mineral, fat or dietary fibre. Whole grains, legumes and nuts can contribute thiamine.

Iron is needed to synthesise haemoglobin, the oxygen-carrying protein in red blood cells. When iron intake or absorption is inadequate, haemoglobin production may fall, causing iron-deficiency anaemia with tiredness, pallor and reduced work capacity. Bone weakness is more closely associated with inadequate calcium or vitamin D, while obesity and dehydration have different causes.

Iodine is required for the thyroid gland to make thyroid hormones, which regulate metabolism, growth and development. When iodine intake is inadequate, the thyroid may enlarge in an effort to capture more iodine, producing goitre. Night blindness is associated with vitamin A deficiency, scurvy with vitamin C deficiency and rickets mainly with vitamin D deficiency.