Pros and cons
Pros
- Individuals need not be literate
- Covers usual diet in detail so only one interview is necessary for the particular time period under consideration
- Details of individual foods are obtained
- Comprehensive information is obtained about foods eaten less regularly
- Energy and most nutrients can be estimated reasonably accurately
Cons
- It is essential to have well trained interviewers with a good knowledge of local food
- The resulting data depend heavily on the skill of the interviewer
- Older individuals may become fatigued and unable to complete the interview in one session; a typical session lasts 60-90 minutes
- The individual may not remember everything they usually consume leading to recall bias
- The method is difficult for those with erratic eating habits such as shift workers
- Individuals may over-report ‘good’ foods and under-report intake of ‘bad’ foods
- It may be difficult for the individual to assess portion sizes of past meals although the interviewer can use photographs or food models to aid this
- It is difficult to adapt for telephone interview, self-completion or computer completion by individual and necessitates a home visit
- Individual food coding is necessary - this is time consuming requiring trained staff and is consequently expensive.