By the end of this chapter, you will be able to:
Mastering these skills will help you create nutritious, balanced meals that improve health and wellbeing in real-world food service and care settings.
Food composition knowledge is fundamental for food and beverage professionals in Kenya as it directly influences menu planning, nutritional balance, and customer satisfaction. Understanding the constituents of food allows operators to design meals that meet health standards and dietary guidelines, ensuring clients receive wholesome and safe nourishment. This chapter explores the essential terms related to food composition, the components of a balanced diet, and the methods used to assess nutritional adequacy, all within the context of food and beverage operations.
The terminology of food science gives cooks, caterers, dietitians and food and beverage managers a common language for describing what food contains and how it serves the body. Using these terms correctly allows a menu planner to read a food composition table, explain a dish to a guest with special needs and plan meals that keep customers healthy. The terms below are used throughout this unit, so each must be clearly understood before moving to the components of a balanced diet and the interpretation of food composition tables. Example: the catering manager of a girls' secondary school in Wajir uses these terms when agreeing a weekly menu with the school nurse.
Food is any substance, solid or liquid, that is eaten or drunk and that supplies the body with energy, materials for growth and repair, and substances that regulate body processes. It may come from plants (cereals, legumes, vegetables, fruits), from animals (meat, milk, eggs, fish) or from other sources such as salt and water. Food also has social and cultural roles: it is shared at ceremonies, marks hospitality and expresses identity, which is why menus must respect local food habits as well as nutrition.
Food composition is the make-up of a food in terms of its chemical and nutritional constituents: water, carbohydrates, proteins, fats, vitamins, minerals, dietary fibre and other compounds such as phytochemicals. It is normally expressed per 100 g of the edible portion and recorded in food composition tables. Composition varies with variety, soil, season, maturity, storage and cooking method; for example, boiling leafy vegetables for a long time lowers their vitamin C. Example: the nutrition clinic of a sub-county hospital in Moyale compares the composition of camel milk and cow milk when advising mothers on feeding young children.
Nutrients are the chemical substances in food that the body needs to produce energy, build and repair tissues and regulate body processes. They are grouped into six classes: carbohydrates, proteins, fats, vitamins, minerals and water, with dietary fibre usually added as a seventh component of the diet. Nutrients are described as essential when the body cannot make them in sufficient amounts and they must come from food, for example essential amino acids and essential fatty acids.
Nutritional requirements are the amounts of energy and of each nutrient that a person needs every day to stay healthy, grow and be active. They depend on age, sex, body size, physical activity, climate and physiological state such as pregnancy, breastfeeding or illness. A road construction worker needs far more energy than an office clerk, and a pregnant woman needs more iron and folate than other adults. Requirements are published as recommended intakes, which food service staff use to plan portion sizes and menus (see 1.4).
Macronutrients are nutrients needed by the body in large amounts, measured in grams per day. They are carbohydrates, proteins and fats, which supply energy, together with water, which is needed in the largest quantity of all. Each gram of carbohydrate or protein supplies about 4 kcal (17 kJ) and each gram of fat about 9 kcal (37 kJ).
Micronutrients are nutrients needed in small amounts, measured in milligrams (mg) or micrograms (µg) per day. They are the vitamins (such as vitamins A, B complex, C and D) and the minerals (such as iron, calcium, iodine and zinc). Although needed in tiny amounts, a shortage causes serious deficiency diseases such as anaemia, night blindness and goitre, which are covered in Chapter 2.
A balanced diet is one that contains all the nutrients in the correct amounts and proportions to meet a person's needs, without excess. In practice it is achieved by eating a variety of foods from all the food groups every day: energy foods, body-building foods, protective foods, a little fat, and enough clean water. A plate of rice with beans and beef stew, cabbage and a slice of pawpaw is a balanced meal, while a plate of chips with soda is not. Example: a children's day care centre in Isiolo plans its lunch so that every plate carries a cereal, a legume or meat, a green vegetable and a fruit.
Food additives are substances added to food on purpose to preserve it, improve its colour, flavour or texture, or help in processing. Examples include preservatives such as sodium benzoate, colourings, flavour enhancers such as monosodium glutamate, raising agents such as baking powder, and emulsifiers. In Kenya their use is controlled by Kenya Bureau of Standards (KEBS) standards, and they must be declared on food labels. Additives change the composition of a food and some people react to them, so caterers should know which ones their bought-in products contain.
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Create a free accountThis chapter explored the fundamental concepts of food composition, starting with clear definitions of key terms and the components that constitute a balanced diet alongside methods for their assessment. It provided detailed guidance on interpreting food composition tables, emphasizing macronutrients and energy values, micronutrients, and other elements such as fiber and ash, as well as serving size information and practical uses of these tables. The discussion then moved to nutritional daily requirements, including recommended intake levels, daily amounts, and the purpose of assessing macronutrients and water intake. Special nutritional needs were addressed for distinct groups such as children, adolescents, pregnant and lactating mothers, older adults, and athletes. The chapter also highlighted the principles of planning balanced meals by setting daily nutritional goals, managing portion sizes, ensuring colour diversity, and limiting processed foods to cater for special dietary needs. Finally, the chapter introduced the digestion of foods as a key aspect of understanding nutritional deficiencies and related disorders.
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