Table 4.
Studies reporting changes in portion size choice (self-selected portion size).
| Authors, Country | Study Design | Tool | Population | Main Results |
|---|---|---|---|---|
| Almiron-Roig et al. 2016 [77]; 2019 [78] UK |
Randomized crossover trial including a qualitative sub-study 4 weeks (2 weeks with each tool) |
Set of calibrated crockery (plate, bowl, glass) Set of plastic serving spoons (CHO, PRO, FV) |
Adults with overweight and obesity (n = 29) | Both tools increased PSs of vegetables and helped decrease PSs of chips and potatoes (self-reported data) |
| DiSantis et al. 2013 [50] USA |
Randomized crossover trial 8 days (school lunch) |
Dishware sizes:
|
(5–6 y old children) (n = 42) |
Chid-size dishware reduced self-served PSs when compared to adult-size dishware. Food liking and meal format (unit entrée) enhanced this effect |
| Fisher et al. 2013 [46] USA |
2 × 2 Randomized crossover trial | Serving spoon sizes: tablespoon and teaspoon Amount of entrée available: 275g and 550g |
4–6 y old children (n = 60) |
Teaspoons reduced entrée serving size by 11.5% vs. using tablespoons. Exposure to larger PS of entrée increased serving size by 40%. |
| Hughes et al. 2017 [75] USA |
Two randomized crossover trials 1 day |
|
Healthy adults n = 70 Study 1 n = 40 Study 2 |
Calibrated plate reduced self-selected PSs of all foods. Vegetables serving sizes remained below the recommended portion sizes on both dishes |
| Koh and Pliner, 2009 (Study 4) [52] Canada |
Mixed-methods randomized controlled trial (crossover and parallel) 1 day |
|
Women, with and without overweight (n = 57) |
The small plate (but not the large) induced participants to self-serve less in the sharing condition vs. the non-sharing condition. Eating with friends led to self-serving more food than eating with strangers (effect of acquaintance) |
| Kroeze et al. 2018 [64] Netherlands |
Observational Study 9 months |
Web based PortionSize@warenessTool (educational on-line program consisting on a digital dish-up for poerion size knowledge and awareness) as part of a combined educational intervention consisting of two phases (3 and 9 months (n=66, 3 months; n=159, 9 months; see Table S1) (SMARTsize)] |
Adults with overweight and obesity (n = 225) | Intervention improved self-reported strategies to control food portion size after 3 months (i.e., prepare low-calorie dishes, intention to consume smaller portions and the use of portion control strategies). Individual counseling had no impact on outcomes |
| Libotte et al. 2014 [73] Switzerland |
Parallel randomized controlled trial (fake buffet) 1 day |
Dishware sizes:
|
Adults, normal weight (n = 83) |
Plate size did not have an effect on self-served total energy of the meal. Large plate promoted larger serving sizes for vegetables |
| Robinson et al. 2016 [27] U.K. |
Parallel randomized controlled trial 1 day |
|
Adults with normal weight and overweight n = 31 Small bowl n = 30 Large bowl | The small bowl induced participants to self-serve more popcorn (4 times) vs. the large bowl (3.5 times) |
| Rollo et al. 2017 [68] Australia |
Three-arm randomized controlled trial |
|
Adults with normal weight and overweight (n = 90) | ServAR tool was well accepted and found easy to use. Moreover, it improved accuracy and consistency of PS estimates compared to the information and control group (actual data on serving sizes not reported) |
| Van Kleef et al. 2012 [60] USA |
Parallel randomized trial 1 day |
|
Normal weight undergraduate students Large Bowl (n = 37) Medium Bowl (n = 30) |
Large-size serving bowls promoted to self-serve 77% more pasta vs. the medium-size bowls (reduction of 44% with the small bowl) |
| Van Ittersum and Wansink 2013 [48] USA |
Randomized crossover trial 4 days (school) |
|
6–12 y olds classed as extroverted or intoverted (n = 18) | Small bowl reduced cereal self-served PSs by 44%, especially for extroverted children |
| Wansink et al. 2006 [61] USA |
Parallel semi-randomized trial 1 day (professional social event) |
|
Adults (Nutrition experts) (n = 85) |
Small bowl reduced self-served ice cream PSs by 24%. The small ice-cream scoop reduced (a) the amount of self-served ice cream by 12% regardless of bowl size (effect most notable with the small bowl); and (b) the amount loaded onto each scoop (2.2 vs. 3 oz). Although the small spoon increased the number of tablespoons, this was not enough to increase consumption |
| Wansink and Van Ittersum 2013 (Study 2) [62] USA |
Observational Study 1 day (Chinese buffet restaurant) |
|
Adults with overweight (n = 43) | Eating with a small plate reduced total energy intake by 34% |
| Wansink and Van Ittersum 2013 (Study 3) [62] USA |
Parallel trial 1 day (conference buffet on changing health behavior) |
|
Adults (n = 209) | Eating with the small-size plate reduced self-serving food volume (number of trays served at group level). The large plate increased the amount of meat and fish served as well as vegetables and salad |
| Wansink et al. 2014 (Study 1) [49] | Parallel randomized controlled trial 1 day (schools) |
|
Pre-school aged children with obesity (n = 69) | Children requested less cereal (served by adults) with small bowl (reduction of 47%). |
| Wanskink et al. 2014 (Study 2) [49] | Randomized crossover trial 2 days (summer camp) |
|
6–12 y old children (Low-income families) (n = 18) | The small bowl reduced the amount self-selected (served by adults) by 41% compared to the large bowl. |
Abbreviations: CHO, carbohydrate; FV, fruit and vegetables; PRO, protein; PS portion size. The term calibrated is used to describe a portion control utensil with either printed indicators or segments separated with raised edges (3D). The term serving size is used as a proxy for self-selected portion size, as stated in the original publication. For full details please see Supplementary Table S1.