National food survey

Key facts

Survey coverage:	Great Britain
Set Sample size:	10,500
Response Rate:	65%
Type of survey:	Face-to-face interviews + diary

Why is the survey carried out?

The National Food Survey (NFS) is the longest-running continuous government social survey having originally been set up in the 1940s to monitor the diet of the urban 'working class' population during the war years. In 1950 it was extended to cover all households in the general population and to collect data on food consumption and expenditure.

Among many uses of the survey are providing information to the Retail Prices Index, identifying changes in food expenditure and consumption over time, and monitoring progress towards targets set out in the White Paper 'The Health of the Nation'. This latter has set targets for the proportion of food energy from total fat and saturated fatty acids to be no more than 35% and 11%, respectively, by the year 2005.

The survey is commissioned by the Department for Environment, Food and Rural Affairs (DEFRA) and has been carried out by Social Survey Division (SSD) since 1996. At the same time the survey was extended to Northern Ireland for the first time and is partly funded by the Department of Agriculture and Rural Development (DARD) with data collection sub-contracted to the Central Survey Unit of the Northern Ireland Statistics and Research Agency.

How is the survey done?

In Great Britain, a sample of addresses is selected from the Postcode Address File (a comprehensive list of all delivery points - postal delivery addresses - in Great Britain) and fieldwork takes place continuously throughout the year.

After a short interview, the household member who does most of the food shopping is asked to keep a seven-day diary in which all food and drink bought by members of the household is recorded, including the weight or volume, and cost. In addition, at about half the households, information is collected about food and drink consumed outside the home. Each member of the household aged 11 or over is given a diary in which all personal expenditure on snacks, meals, sweets and drinks is recorded.

In 1998, interviews and completed diaries were obtained at about 6,000 households, a response rate of 65%.

SSD are responsible for all aspects of the survey up to the production of a data file for DEFRA. In 1998, SSD became responsible for carrying out all edit checks on the data and providing the final clean data file to DEFRA.

Future Developments

There are a number of overlaps between the information collected on the NFS and the Family Expenditure Survey (FES) commissioned by the Socio-Economic Division (SED) of the Office for National Statistics (ONS). During 1998-99 a pilot study was carried out examining the viability of merging these two surveys. The report of this study concluded that the merger of the two surveys could be feasible provided the burden on respondents was reduced. SSD wrote a plan outlining a package of development work over 1999 and 2000, which also included reviewing the current processing system, with the aim of introducing a merged survey in April 2001. This development plan was accepted by DEFRA and SED.

Food Wastage Pilot Survey

A separate Food Wastage Pilot Survey was carried out in 1998-99 to identify a method to enable DEFRA to estimate what proportion of food and drink purchased is not consumed (i.e. is thrown away as either inedible or not wanted).

Three methods of recording waste food and drink were piloted with fifty households taking part in each method. Each method involved respondents recording all items of waste food and drink in a seven-day diary, and the reason for waste. The amount wasted was identified in one of three ways:

• respondents were asked to describe the amount of waste for each item;
• respondents were asked to weigh each item of waste;
• respondents collected all items of waste in one of ten containers that were later collected by the interviewer.

The survey found that weighing waste food and drink was the most appropriate method for obtaining data on the quantity of waste. This method was most acceptable to respondents and provided data of higher quality.

Where can the results be found?

DEFRA publish results quarterly and produce an annual report in the November of the year following fieldwork. The latest report available is 1998 National Food Survey which was published in 1999 and is available from The Stationery Office

The latest quarterly and annual NFS Statistics news Releases and a range of other statistics can be found under the heading "Statistics" at http://www.defra.gov.uk

For more information about SSD or the surveys we carry out contact:
SSD Project Support Branch Tel: +44 (0)20 7533 5500 or e-mail: ssdpsb@ons.gov.uk

This page last revised: Monday, 29 October 2001