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. This could result in no overall benefit of reducing food portion sizes. The investigators tested the hypothesis that reductions to the portion size of components of a main meal will only result in significant compensatory eating when the reduced portion size is no longer visually perceived as 'normal'. In a crossover experiment, participants were served different sized portions during lunch and dinner over 5 days: a 'large-normal', a 'small-normal', and a 'smaller than normal' portion. Intake from all other meal components consumed in the laboratory were measured.
Interventions
BEHAVIORALportion size
Smaller than normal portion size - the intervention is the main meal component size perceived as 'smaller than normal' that participants are provided with during lunch and dinner in the laboratory. Small-normal portion size - the intervention is the main meal component size perceived as 'small-normal' that participants are provided with during lunch and dinner in the laboratory. Large-normal portion size - the intervention is the main meal component size perceived as 'large-normal' that participants are provided with during lunch and dinner in the laboratory.
Sponsors
Medical Research Council
University of Liverpool
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* willing to consume the test foods * BMI between 22.5 - 32.5
Exclusion criteria
* food allergies, intolerances or specific dietary requirements (including being vegetarian or vegan) * history of eating disorders * taking medication which affected appetite * participated in a portion size studies in the past 12 months, or in dieting or weight loss trials in the past 4 weeks
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Acute compensatory energy intake | Immediate (within single meal occasion) | Energy intake from main meal components that are not varied by portion size |
| Total meal energy intake | Immediate (within single meal occasion) | Energy intake from all main meal components (including those that are and are not varied by portion size) |
| Total daily energy intake | Over 5 x full days | Energy intake from all foods consumed, including those provided in the laboratory and those self-reported |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Moderate-vigorous physical activity | Over 5 x full days | Moderate-vigorous physical activity (recorded using accelerometer device) |
| Discretionary Leisure-time physical activity | Over 5 x full days | Discretionary Leisure-time physical activity (recorded with self-report measure International Physical Activity Questionnaire) |
| Appetite | Over 5 x full days (measured before and after each meal occasion) | Hunger and fullness sensations before and after laboratory-based meals (self-reported on visual analog scales anchored at 0 'not at all' to 100 'extremely') |
Countries
United Kingdom
Outcome results
None listed