Expectancy versus experience - Comparing Portion-Size-Effect during pre-meal planning and actual intake.

Area of Science:

• Behavioral Science
• Nutritional Science
• Psychology

Background:

• The Portion-Size-Effect (PSE) significantly influences food intake.
• Limited understanding exists regarding PSE's impact on intended consumption (Expected Intake).
• The role of food cues (e.g., images, descriptors) in modulating PSE during pre-meal planning is unclear.

Purpose of the Study:

• To compare the Portion-Size-Effect on intended versus actual food consumption.
• To investigate how food cue presentation influences Expected Intake.
• To determine if PSE is stronger in pre-meal planning than in actual intake.

Main Methods:

• A within-subject design study with 62 participants.
• Participants rated Expected Intake for pasta portions (400g, 600g, 800g) with varying food cues.
• Actual pasta intake was measured across three ad libitum sessions over 7 weeks.

Main Results:

• Expected Intake showed a near-linear increase with larger portion sizes.
• Actual Intake increased less significantly beyond a certain portion size.
• Pre-meal PSE was comparable to actual PSE for moderate portions but stronger for large portions.

Conclusions:

• Portion size has a greater influence on meal planning (Expected Intake) than on actual food intake.
• Food cue format significantly impacts Expected Intake.
• Future studies should consider portion size and food cues in pre-meal planning research.