Glossary: N

Here you will find definitions of terms used in resources on the Foodsource website. You will also find these definitions on the right-hand side within chapters. If you have any suggestions for new glossary items, let us know here.

2 (1) | A (13) | B (6) | C (16) | D (6) | E (8) | F (12) | G (4) | H (3) | I (7) | L (5) | M (12) | N (7) | O (4) | P (9) | R (8) | S (10) | T (1) | U (2) | W (4) | Y (1) | Z (2)

Nitrogen fixation

Nitrogen fixation is the process through which atmospheric nitrogen (N2) is converted into ammonia (NH3) or related nitrogenous compounds that, when present in the soil, can be utilised by plants. Plants are unable to utilise atmospheric nitrogen (N­2) for plant growth because it is a relatively unreactive gas. There are two main processes through which nitrogen fixation occurs in the food system: artificial nitrogen fixation through the Haber-Bosch process – the process underlying the production of synthetic fertiliser – and biological nitrogen fixation (BNF) through bacteria in the soil and roots of particular plant and tree species such as legumes.

Non-communicable diseases

Non-communicable diseases are diseases which are not passed from person to person. They are often long lasting and generally progress slowly. Examples include cardiovascular diseases, cancer, chronic respiratory diseases and diabetes. Unhealthy diets are one of the major risk factors for non-communicable diseases.

NOVA food classification

The NOVA classification is a system of food classification created by a team of nutrition and health researchers at the University of São Paulo led by Carlos Monteiro. NOVA categorises food products by the ‘extent’ and ‘purpose’ of food processing on the grounds that today this is the main determinant of a food’s nutritional and environmental characteristics. NOVA has four categories: minimally processed food; processed culinary ingredients; processed foods; and ultra-processed foods. Introduced as a framework to measure the impacts of processed foods on human health, NOVA has also been promoted as an alternative to traditional government-approved dietary guidance such as the US MyPlate, the UK Eatwell plate or the Chinese Food Pagoda. While criticised, NOVA is increasingly used as a framework in nutrition science, especially in nutritional epidemiology. The dietary guidelines of Brazil (2014), Uruguay (2016), Ecuador (2018) and Peru (2019) and some reports from the PAHO-WHO have drawn upon the NOVA classification while the French (2019) dietary recommendations advise to reduce the consumption of ‘ultra-transformed’ foods.

Nudge approaches

Nudge approaches are the specific application of nudge theory, whereby the physical or informational environment in which decision making takes place is purposefully changed in order to affect behaviour. On example is using smaller plates to subtly limit overall food consumption in canteens.

Nudge theory

Nudge theory is a concept in behavioural science, economics and political science which tries to achieve non-forced compliance with desired behaviours (e.g. policies). It does this through the adjustment of messaging and the context in which decisions are made, in ways that have been found to predictably affect the motives, incentives, and decision making of individuals and groups of people.

Nutritional epidemiology

Nutritional epidemiology is a sub-branch of epidemiology. This field of study focuses on the distribution and determinants of diseases and other medical conditions in a population. Nutritional epidemiology studies the relationships between dietary patterns, nutrient intake and their impacts upon public health. Common methods in nutritional epidemiology include dietary surveys and cohort studies, by which statistical associations between (say) food consumption and medical conditions such as cancer or obesity are studied.


Coined by the Australian academic Gyorgy Scrinis and popularised by the US journalist and food writer Michael Pollan, nutritionism is a term used to describe and critique the dominant assumption of much nutrition science research – and often of mainstream dietary recommendations – that it is possible to understand the health implications of individual food products as well as dietary patterns in terms of their micro and macronutrient profiles. From this nutritionist perspective, foods are primarily viewed as interchangeable vehicles for the delivery of specific and isolated nutrients. Criticising ‘Big Food’ and the food products it provides, users of the concept tend to highlight the role of food in social and cultural life and argue that healthy dietary patterns mostly consist of home-made meals and dishes that are largely based on unprocessed food ingredients. Scrinis also argues that nutritionism has contributed to the food industry’s use of reformulation and nutrient fortification, which are aimed at improving a food’s nutrient profile.