What is Nutrition & Why Does It Matter? – Kayla Itsines

What Is Nutrition? Key Nutrition Terms Explained!

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What Is Nutrition? Key Nutrition Terms Explained!
What Is Nutrition

Since launching my first website, I’ve been sharing recipes and healthy eating tips with you all. 

As well as sharing tips and suggestions, I believe it is part of my responsibility as a trainer to provide education too.

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So today, I want to help you learn more about a topic that is VERY important for your overall health — nutrition. 

What is nutrition? 

The simple definition of nutrition is how food affects your body’s health. 

While nutrition can be a lot more complicated, with many different factors to consider, I think keeping the above definition in mind is important. 

A more complex definition of nutrition is that it is based on the biological processes of the body that convert food material into energy and/or living tissue. Or, to put it another way, how your body takes in food and absorbs the nutrients that are necessary for you to grow and be healthy. 

Nutrition is what helps your body to function, so it is a really important part of a healthy lifestyle!

Nutrition Definition

Why is good nutrition important?

To put it simply, without the proper nutrition, your body is unable to function at its best. 

Good nutrition allows you to fuel your body and nourish it for growth and repair — something that you need to do every day, especially if you are training regularly. 

When you’re eating a balanced range of vitamins and minerals, as well as getting plenty of energy from your food, this is good nutrition. Eating foods from all of the food groups is the best way to ensure a balanced, nutritionally rich diet. 

These food groups include:

  • Grains
  • Vegetables and legumes

  • Lean meat, seafood, eggs and meat alternatives

  • Dairy products and alternatives

  • Fruit, and

  • Healthy fats.
Importance Of Nutrition

Your nutritional requirements are unique to your body — especially if you have food sensitivities or intolerances to consider. 

Now that you know the answer when someone asks ‘what is nutrition’, I want to help you learn more about some key nutritional terms that I use throughout my blogs. That way, you can follow my healthy recipes and suggestions without getting confused.

Nutrition terms

There are a few nutrition terms you may have come across on my blog, so I’ve included the definitions here to help you understand their meaning. 


As the name suggests, additives are added to food to improve the texture, colour or flavour. They may also be used to preserve the food so that it lasts longer.


This refers to how easily nutrients can be absorbed from your digestive tract into your bloodstream. 

Complete Proteins

Complete proteins

Complete proteins are protein-containing foods, such as eggs, soy and meat, that contain all the essential amino acids that your body requires. Your body isn’t able to produce these ‘essential’ amino acids on its own, so they must be absorbed from the food you eat and must be consumed regularly. 


To have a deficiency means you are lacking in something. So if you have a vitamin B deficiency, for example, you are not getting enough vitamin B to meet your body’s needs. 


When your body loses more water than it takes in, you can become dehydrated. Dehydration can be due to not drinking enough water, due to vomiting or diarrhoea or because of water lost through excessive sweating. 

Energy intake

Your body needs energy to perform even the most basic of functions, from sleeping to maintaining your body temperature. Your energy intake comes from the food and drink you eat. The amount of energy needed by your body depends on your age, height, weight and activity level. 


Fructose is a form of natural sugar found in fruit and in honey. 

Gastrointestinal tract

Your gastrointestinal (GI) tract is an organ system that ingests and digests food, processes it and absorbs the nutrients before expelling the waste. 


A food intolerance is a negative reaction (such as bloating or altered bowel motions) to a food. Unlike a food allergy, a food intolerance does not involve an immune system response. 


Legumes refer to beans and peas from the Fabaceae family. This includes chickpeas, butter beans, adzuki beans, lentils, peas, cannellini beans, red kidney beans and lupins. 


Macronutrients are key dietary nutrients — carbohydrates, protein and fat — that provide the body with energy. Macronutrients are required in large amounts, while micronutrients are needed in smaller amounts. 


Malnutrition refers to a set of health problems that may be caused by a diet containing too much, or not enough, of a particular nutrient. This may be a result of a poor diet or a medical issue that affects nutrient absorption. 


Minerals such as calcium, iron and potassium are naturally found in soil and water and are absorbed through these by plants. Your body obtains minerals from both plants and animals (who also get their minerals from plants). 


Generally classified into two categories, macronutrients and micronutrients, nutrients are the substances in your body that allow it to function. 


The organic definition can vary depending on the region but organic foods generally include those grown without pesticides or chemical fertilisers, without genetically modified (GM) components and with minimal environmental impact. 

Processed Foods

Processed foods

I’m sure this definition will raise a few eyebrows — processed foods refer to any foods that have undergone a ‘process’, even foods that have to be cooked before eating. 

Of course, there are different types of processed foods. Some are processed in order to help our bodies absorb the nutrients, while others are processed to include added sugars, salt or fats. Rather than avoiding all processed foods, reach for whole grains, fruits and vegetables that still contain lots of goodness. 


When a food is refined, such as sugar or white breads and pasta, it has had the outer layers removed or it has been through a form of processing. The process of refining can remove some of the food’s nutritional benefits.

Satiety / satiating

Satiety refers to how ‘full’ you feel after eating. A dish is satiating if it makes you feel as though you’ve eaten enough.  



Any food that is nutrient-dense, providing a high concentration of vitamins and minerals in a small amount. Some examples of superfoods are chia seeds, turmeric and quinoa. 


Vitamins are organically made by plants and animals. They are then absorbed into your body when you eat vitamin-rich foods


A grain food that has retained all parts — the germ, endosperm and bran layers — is known as a wholegrain. 

What is nutrition? Now you know!

Ladies, I really hope you have found this blog helpful! 

I’m a firm believer in gaining as much knowledge as possible when it comes to health and fitness. That means starting with the basics — knowing what nutrition is and what key nutrition terms mean. Now you’ve got a basis to learn even more about healthy eating!

Are there any other nutrition definitions you want me to explain? Let me know in the comments!

* Disclaimer: This blog post is not intended to replace the advice of a medical professional. The above information should not be used to diagnose, treat, or prevent any disease or medical condition. Please consult your doctor before making any changes to your diet, sleep methods, daily activity, or fitness routine. Sweat assumes no responsibility for any personal injury or damage sustained by any recommendations, opinions, or advice given in this article.

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