Diet, Healthy, Eating Behavior, Obesity
Conditions
Keywords
portion size, socio-economic position, eating behaviour
Brief summary
Reducing food portion size is a potential strategy to reduce energy intake. However, it remains unclear who is most susceptible to the portion size effect (PSE). There are just two studies which have examined the PSE in the context of socioeconomic position (SEP), with mixed findings. In an online trial the PSE on intended consumption of unhealthy snacks was 18-24% larger for participants of lower SEP compared to participants of higher SEP. However, in a recent laboratory study which examined the PSE on total daily energy intake, participants of lower SEP were no more susceptible to the influence of portion size on eating behaviour than participants of higher SEP. Further research is required to elucidate these divergent findings. There is also an absence of evidence examining the moderating role of subjective social status (SSS) - an individual's perceived standing in society - on the PSE. Given evidence that the subjective experience of social class may be associated with health outcomes, the present study examines whether reductions to the portion size reduces daily energy intake, and whether and how SSS (higher vs lower) moderates the PSE. In a crossover experiment, participants will be served all meals in the lab on two separate days, with the portion size of main components at breakfast, lunch and dinner manipulated (i.e. smaller on one day vs larger on the other day). All other foods offered are identical. Food intake from the portion-manipulated breakfast, lunch and dinner, as well as all other meal components (non-portion-manipulated sides, dessert, seconds, snacks, etc.) will be measured, to assess total daily energy intake (kcal).
Detailed description
See Study Protocol attached.
Interventions
BEHAVIORALPortion size manipulation
The intervention will be administered via changing portion sizes of foods served to participants.
Sponsors
European Research Council
University of Liverpool
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Female * UK (United Kingdom) residents, able to visit laboratory in Liverpool * Aged 18 or over * Fluent in English * willing to consume the test foods * Self report willingness to eat test foods * BMI between 18.5 - 32.5kg2
Exclusion criteria
* participation in our previous study * food allergies, intolerances or specific dietary requirements (except vegetarian) * taking medication which affects appetite * currently pregnant * history of eating disorders * currently on a diet to lose weight
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Daily energy intake | Time Frame: 24 hours after intervention administered | Total energy (kcal) consumed from breakfast, lunch, dinner, dessert, snackbox, and any self-reported additional foods. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Energy intake from portion-manipulated foods | Time Frame: 24 hours after intervention administered | Total energy (kcal) consumed from portion-manipulated foods at breakfast, lunch, and dinner |
| Energy intake from non portion-manipulated foods | Time Frame: 24 hours after intervention administered | Total energy (kcal) consumed from other foods (no portion-manipulation) at breakfast, lunch, dinner, snacks, and self-reported foods. |
Countries
United Kingdom
Outcome results
None listed