What is Food?

Food is such an important integral part of all our daily lives that one would think there would be a universally accepted definition to simply describe ‘food’. Alas, this is not so. Formal definitions differ depending on whether one looks from the perspective of nutrition or supply.

Nutritionally defined in medical dictionaries or nutrition textbooks, foods are described as: ‘products derived from plants or animals that can be taken onto the body to yield energy and nutrients for the maintenance of life and the growth and repair of tissues’ (1).

Legal food regulations have a broader sweep effectively defining food as: ‘anything that is intended or offered for human consumption’ (2) which can include animals and plants, prepared or partly prepared; ingredients; additives; anything used in its preparation; anything that comes in contact with that substance, such as processing aids; or chewing gum (3-5). 

Thus, by definition, although food is whatever we eat from a consumption perspective, not everything we eat within food is food (6) from a nutritional viewpoint. The main difference is that some components of food, as well as some substances available to be added to food for consumption, are not nutritionally required.

These days there are 40,000 + foods available on our supermarket shelves. It has become increasingly difficult to separate the essentiality of food from the totality of our food supply dominated by the juggernaut of the processed food industry.

National dietary guidelines aim to translate what we need nutritionally from that available to us. In the Australian Dietary Guidelines (ADG) food is not specifically defined (7). To wean out foods for optimal health from the vast array on the supermarket shelves, food is qualified by adjectives with terms such as ‘whole foods’,nutritious foods’ and ‘discretionary choices’ (8,9). Other national guidelines offer similar yet differing approaches to separating nutritious from less-nutritious foods. National guidelines emphasise a food-based approach or offer different dietary ‘patterns’, yet often the food grouping or patterns separating nutritious from discretionary choices are fundamentally cloaked in terms of nutrients. For example calcium, iron, vitamins and protein are considered nutrients we need. Foods high in these nutrients are grouped within nutritious food groups. In contrast, saturated fat, added sugar and salt are considered nutrients we need less of. Foods high in those nutrients are grouped within discretionary choices. (8,9) Previously considered a food-group, in Australia fats and oils are now classified separately from the five nutritious groups, and divided into ‘healthy fats’ (unsaturated oils and spreads, avocados, nuts, seeds, nut butters) and discretionary choices (eg butter, cream, ghee).

Some foodstuffs found in nature (eg honey, maple syrup), food extractions (added sugars, fats and oils) yield energy (calories / kilojoules) but no appreciable levels of any other nutrient. These can be considered ingredients, as they are rarely eaten as foods on their own. Herbs and spices do not yield any appreciable nutrient and are better described as condiments rather than foods. Tea and coffee also do not yield nutrients (except via the milk or sugar consumed with them) and have a mild stimulant effect through caffeine which acts via the nervous system not through digestion. Thus, they act as drugs, not foods. Alcohol acts as both a food (yielding energy) and as a drug. (6)

Today there are 90,000+ global food-products available sold in packets, jars, bottles, boxes, tubs, and tubes; from supermarkets, other retailers and take-away food outlets. To date, processing effects have rarely been considered in national dietary guidelines and food groupings except for individual foods such as processed meat or individual components such as trans fats. More recently a food classification system (named ‘NOVA’), based on the extent and purpose of industrialised processing, was developed by Brazilian researchers. They coined the term ‘ultra-processed foods‘ for those foods that undergo extensive industrialised processing and refining, with final contents including cosmetic food additives, ingredients, food fractions (such as isolated proteins and modified starches). (10) NOVA classification also considers food products or meals such as pizza and ready-to-eat dishes as sub-categories of ultra-processed foods rather than disaggregating them into components.

Lastly, toxins and contaminants may be present in foods from natural or added sources.

In the scientific literature as well as lay press, expressions have been coined to define certain types of foods: ‘real’ food’, ‘whole food’, ‘natural food’, ‘vegan food’, ‘whole food plant-based food’, ‘organic food’, ‘slow food’, ‘convenience foods’, ‘health food’, ‘functional food’ … to name a few. Rarely is ‘food’ simply defined as ‘food’.

In his book ‘In Defence of Food‘ in 2008, Michael Pollan opened his book with the words ‘Eat food. Not too much. Mainly plants.’ (11) In that book he defined “food” as ‘real, proper, simple food’. However, he then felt a need to elaborate further in 2010 with 63 ‘Food Rules’ to describe what he actually meant by ‘real, proper, simple food’. (12)

Clearly, “food” defined simply as “food” is not so simple.


Disclaimer: Nothing in this article or on this website should be taken as medical or dietary advice. Anyone reading any information provided within should seek advice from their own medical practitioner for any issue, disease, illness or health-related problem they may have. Always seek your own advice from a medical practitioner or dietitian before changing your own diet.



1. Whitney, E; Rolfes, SR; Crowe, T; Cameron-Smith, D; Walsh, A; Understanding Nutrition. Australia and New Zealand Edition. Centage Learning Australia 2014.
2. Food Standards Australia and New Zealand. Standard 1.1.2 – Definitions used throughout the Code -“Food” 2017 [updated 08 September; cited 2018 07 January ]. Available from: https://www.legislation.gov.au/Details/F2017C00715.
3. Tasmanian Government. Food Act 2003. 2015.
4. Food Standards Australia New Zealand is the statutory authority that develops standards on what is allowed in foods in Australia, as well as requirements for labelling and processing standards. .
5. Compliance with the Food Standards Code is monitored by state authorities under various legislations. In Tasmania, the definition of food is within the Food Act 2003.3. Tasmanian Government. .
6. Fox BA, Cameron AG. Food Science, Nutrition and Health. London: Hodder & Stoughton; 1989.
7. National Health and Medical Research Council. Eat For Health: Australian Dietary Guidelines Summary. Canberra: National Health and Medical Research Council, 2013.
8. National Health and Medical Research Council. Eat For Health. Australian Dietary Guidelines. Providing the Scientific Evidence for Healthier Australian Diets. 2013.
9. National Health and Medical Research Council. Australian Dietary Guidelines. Glossary.
Whole foods are defined as ‘foods themselves for example fruit, vegetables, bread, pasta, lean meat, milk, yoghurt and not the food component for example calcium, iron, protein’.
Nutritious foods are that which ‘make a substantial contribution to a range of nutrients, have an appropriate nutrient density, and are compatible with the overall aims of these guidelines’ and listed as fruit; grain and cereals; meat, fish, poultry, eggs, legumes, nuts and seeds; milk and alternatives.
Discretionary foods are ‘foods and drinks not necessary to provide the nutrients the body needs, but may add variety’ and are described as those high in saturated fat, sugar, salt and alcohol; such as many biscuits, cakes, pastries, pies, processed meats, commercial burgers, pizza, fried foods, potato chips, crisps, and other savoury snacks.
10. Monteiro, C et al. Ultra-processed foods: what they are and how to identify them. Public Health Nutr. 2019 Apr; 22 (5): 936-941.
11. Pollan, Michael. In Defence of Food. 2008. Penguin Books. London.
12. Pollan, Michael. Food Rules. 2010. Penguin Books. London.