Table 1 Strengths, limitations and feasibility of dietary assessment methods at sea (Adapted from [18] additionally with authors’ opinion

24-h dietary recalls

Recall bias, trained interviewers required, Interviewer bias, multiple days required to assess usual intake

Provides detailed intake data; relatively small respondent burden (literacy not required).

Would be applicable by using interactive computer-based technology.

Dietary records

Respondents should be trained before the study, respondents should have high level of motivation, possible under-reporting, expensive and time-consuming; multiple days required to assess usual intake

Provides detailed intake data; no interviewer required; no recall bias

Would be applicable by using interactive computer-based technology.

Dietary history

Trained interviewers required, time consuming, high costs

Assess usual dietary intake over a long period of time, self-administrative

Not applicable because of complicated measurements and possible related errors. Also, it would be problematic for application among multi ethnicity groups.

Food frequency questionnaire

Specific to study groups and research aims; uses a closed-ended questionnaire; low accuracy (recall bias); requires accurate evaluation of developed questionnaires

Assesses usual dietary intake simply, cost-effective and time saving, suitable for epidemiological studies. Requires a certain degree of literacy.

Might be applicable by using interactive computer-based technology. But factors including culture, ethnicity and individuals’ preferences that can influence diet should be considered precisely in development of the questionnaire.

Food consumption record

Trained staff required, not suitable among those who eat in group

Ease of application among those with low literacy.

Not applicable among those who eat in group.