Table 2.

Criteria for assessing study quality

Points awarded.	Method	Description
Study design
3	Prospective	Each participants is surveyed before the pandemic and during the pandemic and their dietary intake compared between time points
2	Pre/post	Separate groups of participants are surveyed either before or during the pandemic, and differences in the intake are based on group comparisons
1	Retrospective	Cross-sectional design in which participants surveyed during the pandemic are asked to recall their diet before the pandemic and/or comment on changes
Dietary assessment method
7	Objective assessment	Dietary intake is either observed by trained study staff or ascertained by a blood-based nutritional marker
6	Multiple 24-h recall	Participants are asked to recall their dietary intake for 24 h, in the presence of trained study staff, for at least one weekend day and one weekday
5	Single 24-h recall/validated FFQ	Participants are asked to recall their dietary intake for 24 h, for a single 24-h period, or participants complete a validated FFQ
4	Validated study-specific questionnaire	Participants complete a questionnaire developed for the study under question, which asks about the intake of several foods and has been validated in previous analyses
3	FFQ	Participants complete an FFQ which has not been previously validated
2	Study-specific questionnaire	Participants complete a questionnaire developed for the study under question, which asks about the intake of several foods which has not been validated in previous analyses
1	Study-specific single-item question	Participants are asked a single question about their intake (usually relating to a single food item)

Abbreviations: FFQ food frequency questionnaire