Bad popcorn in big buckets: portion size can influence intake as much as taste.

OBJECTIVE It is often believed that people overeat the foods they like. We investigated whether environmental cues such as packaging and container size are so powerful that they can increase our intake of foods that are less palatable. DESIGN, SETTING, AND PARTICIPANTS In a 2 x 2 between-subjects design, 158 moviegoers in Philadelphia (57.6% male; 28.7 years) were randomly given a medium (120 g) or a large (240 g) container of free popcorn that was either fresh or stale (14 days old). Following the movie, consumption measures were taken, along with measures of perceived taste. OUTCOME MEASURES AND RESULTS Moviegoers who were given fresh popcorn ate 45.3% more popcorn when it was given to them in large containers. This container-size influence is so powerful that even when the popcorn was disliked, people still ate 33.6% more popcorn when eating from a large container than from a medium-size container. CONCLUSIONS AND IMPLICATIONS Even when foods are not palatable, large packages and containers can lead to overeating. The silver lining of these findings may be that portion size can also be used to increase the consumption of less preferred healthful foods, such as raw vegetables.