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Lesson 1 of 7 6–8 min read
Nutrition Basics: What Is Nutrition?
Before calories, labels or meal ideas, it helps to know the vocabulary. This lesson introduces the main nutrients and how they fit together.
What is nutrition?
Nutrition is the process of taking in food and using it for energy, growth, repair and the normal running of the body. The word is also used for the study of how food and drink affect health.
What are nutrients?
Nutrients are substances in food that the body uses. They are usually grouped as follows:
- Carbohydrate – includes sugars and starches. Found in foods such as bread, rice, pasta, potatoes, fruit and pulses. A main source of energy.
- Protein – made of amino acids, used to build and repair body tissues. Found in foods such as meat, fish, eggs, dairy, beans, lentils, tofu and nuts.
- Dietary fat – provides energy, helps the body absorb fat-soluble vitamins (A, D, E and K), and supplies essential fatty acids. Found in oils, butter, nuts, seeds, oily fish and many processed foods.
- Fibre – a type of carbohydrate found in plant foods that is not fully digested. It supports normal digestion. Found in wholegrains, vegetables, fruit, pulses, nuts and seeds.
- Vitamins – organic compounds needed in small amounts for many body processes (for example vitamin C or the B vitamins).
- Minerals – inorganic elements such as calcium, iron, potassium and zinc, also needed in small amounts.
Water is also essential, although it provides no energy.
Macronutrients vs micronutrients
Macronutrients are needed in larger amounts (measured in grams) and include carbohydrate, protein and fat. These three nutrients provide energy.
Micronutrients – vitamins and minerals – are needed in much smaller amounts (often milligrams or micrograms). They do not provide energy, but are still essential. “Micro” describes the amount needed, not their importance.
A first look at kcal and kJ
The energy in food is measured in kilocalories (kcal, often just called “calories”) or kilojoules (kJ). Many food labels show both. You'll learn how these work, and how to convert between them, in Lesson 2: Calories & Energy.
Variety and balanced eating
No single food provides every nutrient in the amounts the body needs. Eating a variety of foods from different groups makes it more likely you get a wide range of nutrients. The WHO describes a healthy diet as including a mix of foods such as fruit, vegetables, legumes, nuts and whole grains, with limits on free sugars, salt and certain fats.
Country-specific guidance: United Kingdom
The Eatwell Guide is the UK Government's healthy-eating model, published by the Office for Health Improvement and Disparities and promoted by the NHS. It shows the proportions of food groups recommended for a healthy, balanced diet: fruit and vegetables; potatoes, bread, rice, pasta and other starchy carbohydrates; beans, pulses, fish, eggs, meat and other proteins; dairy and alternatives; and oils and spreads.
This guidance applies to the UK. Other countries publish their own food-based dietary guidelines (for example MyPlate in the United States), which differ in format and detail. Check the guidance from the health authority in your own country.
Check your understanding
4 questions. Choose an answer for each, then check.
Answer all 4 questions to check your work.
Lesson summary
- Nutrition is how the body takes in and uses food.
- Main nutrient groups: carbohydrate, protein, fat, fibre, vitamins and minerals (plus water).
- Macronutrients are needed in grams; micronutrients in much smaller amounts.
- Food energy is measured in kcal or kJ.
- Variety helps cover a wide range of nutrients; follow the guidance for your country.