24-hour recall
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.
The strengths and weaknesses are detailed in the table below:
| Strengths | Weaknesses |
|---|---|
| Can provide detailed information as it is open ended. This provides good estimates of short-term intake of absolute intakes (good for when comparing when specific dietary recommendations) | Does not capture irregularly consumed foods |
| Provides data that can be analysed in different ways | Relies on good participant episodic memory |
| Can provide some contextual information depending on design e.g. who else was present when eating | Relies on recalled and estimated portion sizes |
| Useful for capturing intake in culturally diverse contexts | A single day is not representative of usual individual intake due to day-to-day variability (use of multiple 24-hour recalls over a sufficient number of non-consecutive days and seasons can overcome this) |
| Moderate participant burden and high compliance (depending on number of days) | A single day can under/over-estimate habitual intakes of certain nutrients from irregularly consumed foods |
| When used in epidemiological associations, estimates may be attenuated as day-to-day variation is not accounted for | |
| Moderate to high researcher burden due to coding | |
| Can be expensive and time-consuming to code | |
| Forgotten items are common (exclusions) and intrusions (items included but were not consumed) also occur |