Portion Size
Conditions
Brief summary
Reducing food portion size is a potential strategy to reduce energy intake. However it is unclear at what point consumers compensate for reductions in portion size by increasing energy intake from other items. The investigators tested the hypothesis that reductions to food portion size will only result in significant compensatory eating when the reduced portion size is no longer visually perceived as 'normal'. In two within-subjects experiments, participants (Study 1: N = 45, M BMI = 26.9; Study 2: N = 37, M BMI = 26.9; 51% female) were served different sized portions of a lunchtime meal on three occasions: a 'large-normal', a 'small-normal', and a 'smaller than normal' portion. Both the reduction from 'large-normal' to 'small-normal' and from 'small-normal' to 'smaller than normal' portions represented the same change in food volume and energy content (84g, 77kcal Study 1; 98g, 117kcal Study 2). Participants were able to serve themselves additional helpings of the same food (Study 1), or dessert items (Study 2).
Interventions
BEHAVIORALportion size
Smaller than normal portion size - the intervention is the meal size perceived as 'smaller than normal' that participants are provided with during a lunchtime session in the laboratory. 'Small-normal' portion size - the intervention is the meal size perceived as 'small normal' that participants are provided with during a lunchtime session in the laboratory. 'Large normal' portion size - the intervention is the meal size perceived as 'large normal' that participants are provided with during a lunchtime session in the laboratory.
Sponsors
Medical Research Council
University of Liverpool
Study design
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* general liking and willingness to consume the test foods in each study
Exclusion criteria
* food allergies, intolerances or specific dietary requirements (including being vegetarian or vegan) * a history of eating disorders;
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Meal energy intake | Immediate | Energy intake from the served portion |
| 'Compensatory' (additional) energy intake | Immediate | Energy intake from additional food provided for consumption after the portion-manipulated meal |
Countries
United Kingdom
Outcome results
None listed