Diet diaries
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.
The strengths and weaknesses are detailed in the table below:
| Strengths | Weaknesses |
|---|---|
| Provides detailed information on short-term intake leading to good estimates of total dietary/nutrient intake | Not suitable for retrospective study |
| Provides data that can be analysed in different ways | Does not capture irregularly consumed foods |
| Can provide some contextual information depending on design e.g. who else was present when eating | Potential for reactivity (changes of usual food choice) as number of days increases |
| Limited reliance on memory | Good literacy and numeracy skills needed |
| Relies on participants to estimate portion sizes | |
| High participant burden, particularly as the number of days increases | |
| High researcher burden as coding can be complicated |