In epidemiological research, diet is often assessed using dietary assessment tools (DATs). The aims of most DATs are to collect an accurate record of habitual food and nutrient intake for a group of individuals. This can be extremely difficult, particularly due to the significant variation in dietary intake within individuals. There has been extensive work in developing DATs. There are two online resources, both supported by the Medical Research Council, which give a comprehensive overview of DATs:
- Nutritools (opens new tab) developed by the DIET@NET partnership
- DAPA Measurement Toolkit (opens new tab) developed by the University of Cambridge (also supported by the NHS, European Union and InterConnect Project)
Each DAT has specific strengths and weakness and the one used should be suitable for the research question, overall study design and population of interest. The reliability and validity of these tools have been discussed in Willett 2013  and guidance on use of DATs is given in the online resources listed above. The tables below (information adapted from Willett and Nutritools.org [6, 15]) give a brief overview of the main DATs used in the original CLOSER partner studies.
Click below for an introduction to each of these DATs:
Retrospective in-depth interview capturing everything the participant had to eat or drink over the past 24-hour period. This can be administered in person over the phone or online. There is opportunity to probe for additional foods and food preparation methods and to use prompts and aids for portion size estimation.
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Retrospective method where the participant reports frequency of usual consumption of a specific food/food group over a pre-defined period of time. Questions on quantity can also be included (semi-quantitative FFQ or fully-quantitative FFQ). The number of food/drink items included in the FFQ vary and can be long (comprehensive FFQ) or short. It can be administered in person or over the phone or self-completed on paper or online.
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Prospective methods in which the participant records everything consumed over a number of days. It is best when these days include a mixture of weekend and weekdays. The amount of food/drink consumed can be estimated using household measures or weighed in the home. These diaries can include prompts and photographs to aid description of portion sizes and can be completed in paper format or online.
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Explore additional background detail:
- Objective and outline of this guide
- Dietary research in context
- Estimating nutrient intakes from DATs
Learn more about the individual studies covered by this guide and their dietary measurements:
- Overview of dietary information in selected CLOSER studies
- Hertfordshire Cohort Study (HCS)
- 1946 National Survey for Health and Development (NSHD)
- 1958 National Child Development Study (NCDS)
- 1970 British Cohort Study (BCS70)
- Understanding Society: The UK Household Longitudinal Study (UKHLS)
- The Avon Longitudinal Study of Parents and Children (ALSPAC)
- Southampton Women’s Survey (SWS)
- Millennium Cohort Study (MCS)
Learn about harmonisation in the context of dietary data:
- Acknowledgements and copyright information for this guide
- References for this guide
- Download the full guide as a PDF
This page is part of the CLOSER resource: ‘A guide to the dietary data in eight CLOSER studies’.