Table 1.

PICOS criteria for inclusion and exclusion of studies (based on [33]).

Criterion	Description
Population	Healthy adults and children or subjects with a controlled clinical condition not affecting their day-to-day activities.
Intervention	Any intervention in which an instrument or tool is used to control food/drink portion size irrespective of its validation status and not requiring significant professional guidance or a clinical setting for the user to be able to use it appropriately (i.e., tools providing direct feedback to the user via guidelines for appropriate consumption or by restricting the amount of food than can physically be served or consumed).
Comparison	Other tool size/design/type or control condition; no tool.
Outcome	Range of portion control tools currently available and their effect on poriton size awareness, choice and intake; weight loss, BMI change, experiential and other relevant data.
Study design	Any study design involving the application of a tool or instrument to control food portion size including 3D tools, 2D educational aids and/or technology-based tools; review papers with relevant references.