Changing Portion Size Descriptions in a Cafeteria

Changing Restaurant Portion Size Descriptions to Encourage Selection and Intake of Smaller Meals: a Field Experiment

The goal of this this intervention is to test the degree to which a portion size labeling intervention influences consumer selection of smaller portions at two large cafés. The main question it aims to answer is: Do consumers order fewer calories when the portion size label for the smaller entree is called "standard" instead of "small"?

Participants will order lunch as usual in the two cafes (one intervention, one control) for 5.5 months, and all order items will be recorded in the check-out system. One cafe will receive the labeling intervention, while the other will not. Researchers will compare the average calories per order between the two cafes to see if there are differences.

Study Overview

• Status: Completed
• Conditions: Obesity; Weight Gain; Food Preferences; Food Selection
• Intervention / Treatment: Behavioral: Intervention "Standard"

Detailed Description

The investigators will work with two cafés that will start offering two size options for their entrées. The cafés will go through three phases: a baseline phase where there are two portion sizes and no intervention (6 weeks), an intervention phase where the portion size labeling strategy will be implemented (7 weeks), and then a final phase where the portion size intervention is removed (7 weeks). During the baseline period, the smaller-sized entrée will not receive a label, and the larger-sized entrée will be called "Large." During the intervention period for the control café, labeling will stay the same, but in the intervention café, the smaller size will be labeled "Standard" and the larger size will be called "Large." In the post-intervention period, the smaller-sized entrée in the intervention café will have no label so that it resembles the control café.

• Study Type: Interventional
• Enrollment (Actual): 101481
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Courtyard Cafe
    • Boston, Massachusetts, United States, 02115
      • Elements Cafe

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• All customers who make a lunch purchase at the cafes

Exclusion Criteria:

• Purchases made outside of lunch service.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention "Standard"; The smaller entree is labeled "Standard" and the larger entree is labeled "Large."	Behavioral: Intervention "Standard"; The two cafes will offer entrees in two sizes, a smaller and larger size. In the intervention cafe, the smaller size will be labeled "Standard" during the intervention period, and "Small" during all other times. In the control cafe, the smaller size will always be labeled "Small." The larger size will always be labeled "Large" for both cafes during the duration of the study.; Other Names: "Standard"
No Intervention: Control "Small"; The smaller entree is labeled "Small" and the larger entree is labeled "Large."

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average kcal per entree sold	The primary outcome will be the average kcal per entrée purchased.	Daily sales data for 5.5 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of entrée units purchased	Analyzing the number of entrée units purchased will enable the investigators to assess the impact of the intervention on entree sales.	Daily sales data for 5.5 months
Total kcal per transaction	This will allow the investigators to examine whether participants who ordered a reduced-sized entrée were ordering more calories in other parts of the meal (i.e., a dessert).	Daily sales data for 5.5 months
Weekly gross sales	This will allow the investigators to assess whether the addition of a reduced-sized entrée at a lower cost negatively affected lunch service revenue.	Daily sales data for 5.5 months

Collaborators and Investigators

• Sponsor: University of Pennsylvania
• Collaborators: Restaurant Associates
• Investigators: Principal Investigator: Sophia V Hua, PhD, MPH, University of Pennsylvania

Study record dates

Study Major Dates

• Study Start (Actual): January 11, 2024
• Primary Completion (Actual): May 29, 2024
• Study Completion (Actual): May 29, 2024

Study Registration Dates

• First Submitted: February 8, 2024
• First Submitted That Met QC Criteria: February 8, 2024
• First Posted (Actual): February 16, 2024

Study Record Updates

• Last Update Posted (Actual): July 11, 2024
• Last Update Submitted That Met QC Criteria: July 10, 2024
• Last Verified: July 1, 2024

More Information

Terms related to this study

• Keywords: portion size, choice behavior, energy intake, food labeling
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes; Weight Gain
• Other Study ID Numbers: 855090

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Sales data will be made available to interested researchers pending approval from cafe managers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No