Key points about nutrients

  • Food and drinks are made up of a range of nutrients that you use for energy, growth and maintaining healthy tissues. Good nutrition helps you to function well physically and mentally.
  • Nutrition is the study of nutrients and the way we process them.
  • Nutrients fall into 2 main categories – macronutrients (which we need in relatively large amounts) and micronutrients (which are mostly needed in small amounts).
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Macronutrients make up the bulk of our diet and are mainly involved in the supply of energy, but they're also responsible for other activities.

Macronutrients include:

Micronutrients are substances we must get in small quantities from our diet, either because we can’t make them for ourselves or because we can't make them as fast as we need them. They are not an energy source, but are needed in the process of creating energy.

Micronutrients include:

  • vitamins, which are organic compounds (made from carbon)
  • minerals, which are inorganic (not made from carbon).

Read more about vitamins and minerals.

Nutrients are classed as essential or non-essential. Non-essential nutrients are ones your body can make itself, although they may also come from the diet.  Essential nutrients, however, are ones that we can’t make for ourselves in sufficient quantities to meet our needs, so they must be obtained from food.

These nutrients include:

  • minerals
  • most vitamins
  • some amino acids (from which proteins are made) 
  • some fatty acids.

Because we can’t make these, we must regularly choose foods that supply them.

Water is also defined as an essential nutrient because you need more of it than your body can produce. It fills the spaces in and between cells, and is needed for digestion, absorption, transportation, dissolving nutrients and getting rid of waste products. 

Our bodies require a balanced intake of essential, micro- and macro- nutrients to function properly.

  • Not having the right essential nutrients in our diet can result in various deficiency diseases or other disorders.
  • Excess intake of micronutrients can be toxic.
  • Eating more macronutrients (energy) than you need can lead to obesity and related disorders.
  • Not eating enough macronutrients (energy) to meet your energy requirements can lead to weight loss, wasting and disorders related to malnutrition.
  • The balance of various types of nutrients (eg, how much fibre-rich carbohydrate sources versus refined sugars are consumed) can influence the development of disorders.
  • To get a healthy balance of nutrients, it's important to choose mostly minimally-processed foods and to minimise the amount of ultra-processed foods you eat.

A balanced plate of food with protein, carbohydrate, fruit and vegetables

Image credit: Canva

You can generally get all the nutrients you need from:

  • eating a varied and balanced diet consisting mostly of minimally-processed food, and
  • spending some time in the sun.


However, there are times when you can benefit from taking supplements. These include:

 Read more about supplements

We need energy for everything we do, including digesting our food, keeping our body tissues working so we can do things like use our muscles, control our temperature, grow and make new tissues. Energy is released into your body from macronutrients (carbohydrates, proteins, fats) and to a lesser extent alcohol, by a process called oxidation. 

The unit of energy is the kilojoule (kJ):

  • fats yield 37.7 kJ/g (or 9 calories per gram)
  • proteins 16.7 kJ/g (or 4 calories per gram)
  • carbohydrates 16.7 kJ/g (or 4 calories per gram)
  • alcohol yields 29.3 kJ/g. (or 7 calories per gram).

Our personal energy requirements vary with age, gender, body size and activity – so there are different recommendations of how much energy is needed every day for each age and gender group:

Men Inactive kJ Moderate activity kJ
19–30 years 10,800 13,800
31–50 years 11,000 16,100
51–70 years 9,500 12,100
>70 years 7,400 13,600
Women Inactive kJ Moderate activity kJ
19–30 years 8,100 10,500
31–50 years 7,900 10,100
51–70 years 7,600 9,600
>70 years 7,100 9,100

(Source: NRV NZ and Australia, 2006, updated 2017(external link))


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Fitting more fruit & vege into your diet

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust

Reviewed by: Sylvia North, Fearless Nutrition – Integrative Dietitian and Nutritionist

Last reviewed: