Social influence on eating behavior and using serving size as a mitigating factor
There is a lot of attention today given to eating behaviors and patterns that lead to overeating. One factor that leads to overeating is eating as a social function. This study investigated whether there was an effect of the number of people eating together on the amount consumed by each person, and if the effect can be mitigated by making people aware of proper portion size before they eat. The expected results were that female triads would eat more individually than dyads, or those eating alone. In addition, we hypothesized that the participants made aware of proper portion size before their meals would eat less than those that were not made aware of proper portion size. Women (N=99) received a pre-weighed meal of pasta that weighed 710.4 grams. Before the meal, half of the participants were informed of the proper serving size via a questionnaire. After the meal concluded, the amount not eaten per person was weighed to determine the amount consumed and the duration of the meal was recorded. The results partially confirm the hypotheses. Individuals in dyads did eat more than those eating alone. However, individuals in triads did not eat more than individuals in dyads; they ate less. Furthermore, serving size information had no effect on the amount the individuals ate in any group.
INTRODUCTION RESULTS DISCUSSION Social Influences on Eating Behaviors and Using Serving Size Information as a Mitigating Factor Joseph Currin, Washburn University Faculty Advisor: Dr. Joanne D. Altman METHOD N 30 34 33 Mean Age (SD) 23.44 (10.55) 22.15 (8.13) 20.21 (5.39) Mean BMI (SD) 25.47 (5.95) 28.27 (10.24) 25.18 (5.80) Racial Makeup 20 Caucasians, 7 African Americans, 3 Hispanics 30 Caucasians, 2 African Americans, 1 Hispanic, 1 Asian 26 Caucasians, 3 African Americans, 3 Asians, 1 Hispanic There are no significant differences across groups PARTICIPANTS MATERIALS & PROCEDURE • 2(mindful condition) x 3 (group size) between groups ANOVA for amount of food eaten by each individual (in grams) Main Effect for Group Size (p = 0.01) Main Effect for Mindful Condition Interaction between Mindful Condition & Group Size • 2(mindful condition) x 3 (group size) between groups ANOVA for length of meal by each individual Main Effect for Group Size (p < 0.01) Main Effect for Mindful Condition Interaction between Mindful Condition & Group Size • 2(mindful condition) x 2 (group size) between groups ANOVA for length of friendship Main Effect for Group Size (p < 0.01) Main Effect for Mindful Condition Interaction between Mindful Condition & Group Size Participants filled out a demographic survey • Race • Calculate BMI with provided chart • Age • Length of friendship Participants then took a memory test • Look at page with 20 clipart images for 1 minute • Took paper away, wrote down what they could remember • Used to misdirect participants about actual purpose of study, not used or scored Particip ants filled out one of two food intake surveys • This is how mindfulness of serving size was introduced into the groups • Half of the participants filled out each survey • 10 questions • Sample questions below: • Approximately how many servings of pasta, rice, and/or grains do you have in one week? • The food was weighed before the meal. • Participants received 1 ½ times the amount of a proper serving size. • The meal consisted of pasta, marinara sauce, parmesan cheese, and a breadstick • The duration of the meal was timed and recorded • The remaining food was weighed • No one was able to eat all the food provided Cost of obesity in America • Over $70 billion • Treating obesity and obesity related illnesses like diabetes • (Centers for Disease Control & Prevention, 2011) One Third of the US is obese • Sedentary Lifestyle • Overeating • Genetics • Social Environment • Having Obese Friends/Family • (Flegal, Carroll, Ogden, & Curtin, 2010) • Social Facilitation is when the environment enables, demonstrates, or encourages a person to engage in a behavior • Two methods of social facilitation • Distraction • Influence of Others • (Bond & Titus, 1983) People eat more when eating with others (Hetherington, Anderson, Norton, & Newton, 2006) Even presence of others will effect food selection before eating • Students observed choosing food at the university cafeteria • Larger the group of friends going through the line = more food selected • Students were focused on their friends instead of their hunger levels • Young, Mizzau, Mai, Sirisegaram, & Wilson (2009) Mindful Eating • Eating with no distractions • Concentrate on taste, smell, texture, and preparation of food • Eating with no one, no television, no reading • Mindful eating helped patient lose 47 lbs. • (Ergstrom, 2007) Mindful of Serving Size • Hard to do mindful eating, but everyone can be aware of serving size information • Serving size information can be misleading • Being aware of serving size information can prevent overeating PURPOSE Investigate whether a person would eat more in a larger group and if making that person aware of serving size information would mitigate the affect HYPOTHESES Women eating in triads will eat more and longer than those eating in dyads or alone Making participants aware of serving size information will cause individuals to eat the same amount, regardless of group size • When a person compares his/her behavior to the group and changes behavior to match what the group would deem socially acceptable • (Polivy & Herman, 2005) • People modify their behaviors and sometimes do not even realize it FUTURE RESEARCH • Ensure length of friendship between dyads is the same as between the dyads • Run groups with men only, and run groups with men and women only to see if the same effects hold true across genders • Use a more effective method of introducing serving size information ACKNOWLEDGEMENTS Special thanks to Washburn University’s WTE program for providing a research grant to conduct this experiment and to Chartwells, the contracted vendor on campus that runs the dining facility, that prepared and gave a discount on the meals. OBESITY SOCIAL FACILITATION Dined Alone Dined w/Friends Dined Alone & watched TV Ate 18% more than dining alone Ate 14% more than dining alone COUNTERACT • Approximately how many servings of pasta, rice, and/or grains do you have in one week? (For example, one serving of pasta is about the size of two tennis balls) • Additional information was to help participants visualize proper serving size Participants ate meal provided Partially supported • Women in dyads did eat more than women eating alone • Women in triads did not eat more or longer than those in dyads or eating alone • Why?? Those in triads did not know each other as long as those in dyads Social Comparison Theory can explain why triads ate less than dyads FIRST HYPOTHESIS • Two Women • Watched TV • Ate mini pizzas • Served on same tray • Set between two women • All pairs ate the same amount of pizza • Asked participants why they ate amount • Only 3 out of 122 said trying to match partner SECOND HYPOTHESIS Not supported • Making participants aware of serving size information did not cause participants to eat the same amount regardless of serving size Why No support?? • During debrieifing, participants stated they did see the serving size information • Also understood information • Did not apply information to their behaviors Eating behavior is influenced by more than just hunger Not Mindful of Serving Size version Mindful of Serving Size Version Figure 2. Actual length of meal (in minutes) based on the size of the experiment group. Dyads ate longer than singles. Triads did not take longer than Dyads. Triad Figure 1. Actual amount of pasta (in grams) eaten per person based on the size of the experiment group. Dyads did eat significantly more than singles, but triads surprisingly did not eat more than the dyads. Figure 3. Actual length of reported friendship (in years) based on the size of the experiment group. There was a significant difference in the length of friendship between the triads and dyads. • Vartanian, Herman, & Wansick (2008)